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OF ILLINOIS 
LIBRARY 


Presented in 1929 by- 
George William Myers 
Class of 1888 


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cop. 2 


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SPIRAL NEBULA IN URSA MAJOR, KNOWN AS MESSIER 101 
From a photograph taken at the Mt. Wilson Solar Observatory 





A BEGINNER’S STAR-BOOK 


An Easy Guide to the Stars and to the Astronomical 
Uses of the Opera-Glass, the Field-Glass 
and the Telescope 


By Sec ahre 
KELVIN McKREADY( tu rp ky ; ee 
er tt as. 
Mf af b 


ee 


7 


With Charts of the Moon, Tables of the Planets, and Star Maps 


on a New Plan 


Including Seventy Illustrations 


G. P. PUTNAM’S SONS 

NEW YORK AND LONDON 

The Knickerbocker Press 
1912 


COPYRIGHT, I912 
BY 
G. P. PUTNAM’S SONS 


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The Tnickerbocker eel ‘Rew Work 
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To 


; M. anv D. ann G. 


WHO HAVE WATCHED WITH ME AT THE THRESHOLD 





No unregarded star 
Contracts its light 
Into so small a character, 
Removed far from our humane sight, 


But if we steadfast looke 
We shall discerne 
In it, as in some holy booke 
How man may heavenly knowledge learne. 


WILLIAM HABINGTON, 1634. 





‘‘Some amateurs, I am told, believe that their efforts are rendered futile by the more power- 
ful equipment and better atmospheric advantages of other investigators. If this feeling were 
well grounded, it might fairly be asked whether the great observatories are worth their cost. 
For the history of astronomy teaches that much of the pioneer work has been done by amateurs, 
usually with modest means and in unfavorable climatic conditions. We may therefore inquire 
whether useful work of such a nature as to contribute in important degree to the advancement 
of science can still be done with simple and inexpensive instruments. This question may 
at once be answered in the affirmative. Far from believing that recent developments have 
been detrimental to the amateur, I am strongly of the opinion that his opportunities for 
useful work have never been so numerous.’’—A Study of Stellar Evolution, by GEORGE ELLERY 
HALE, Director of the Mt. Wilson Observatory, pp. 243; 23; University of Chicago Press, 1908. 


Preface 


Tuts book has been made in the hope that it will prove of service. It is, in a sense, 
but one effort more to help those who are without technical equipment to claim through 
the unaided eyes, or through simple optical instruments, their heritage in the things of 
the sky. And yet the book would not have been undertaken but for the conviction that 
it represents certain new and useful departures in scope and method. For a fuller state- 
ment of these I must refer to the introductory pages. 

While intended for the general reader I trust it may also prove of value in some of 
our educational institutions. Many a teacher of sound culture and adequate training 
who would like to observe and would like to help others to observe, has had no opportunity 
to know the use and possibilities of the small telescope. Most of the manuals of obser- 
vation assume as already known many of the things that the beginner chiefly desires to 
know—both as to the stars and the instruments employed. 

In dealing with the practical side of observation I have tried, therefore, to be explicit 
and to be definite. I have not avoided repetition but have tried to employ it in the in- 
terest of clearness and usefulness. I have attempted also to meet the small problems the 
very existence of which—when once overcome—the experienced observer has been alto- 
gether too likely to forget. 

I have not given the volume the form or manner of the text-book; for, as already 
stated, it is especially intended for the general reader. And yet as a book for supple- 
mentary use, and as a simple observational manual, it may be employed concurrently with 
any of our modern volumes on astronomy. It is not unlikely that a little actual experience 
in observation will give broader value to the use of such texts both by the general reader 
and by the student, and may add an interest to the theory and mathematics of the 
science. Even where there is no formal course in ‘‘astronomy,’’ the student will find a 
real gain to pleasure, to imagination, and to a larger conception of the universe in the mere 
experience of intelligent observation. It is worth while to know something of the things 
of the sky, not merely from a picture or a lantern slide, but with that sense of actuality 
which comes from seeing the things themselves. 

The volume is also intended for those who wish to add to their knowledge of the skies 
without optical aid of any kind. Even to readers unable to use a telescope, the information 
as to the telescopic objects among the stars, in the moon, etc., is of interest and value. 
While, therefore, such information is kept distinct, it is presented in close connection with 
the more popular discussion of the moon, the planets, and the constellations. Tables 
are included indicating the positions of the planets in their course through the stars, 
month by month, till the year 1931. 

The telescopic objects are grouped directly under the Key-Maps in three different 
classes,—(a) those for the opera-glass and field-glass; (4) those for telescopes of 2 inches, 
and (c) those for telescopes of 3 inches, in aperture. Though almost all the selected 
objects are, therefore, extremely easy, they nevertheless afford abundant opportunity 
for larger instruments. Indeed, I trust that advanced students will not find the general 
apparatus of the book, its diagrams, maps, etc., unsuited to their needs,—for great care 


Vi 


vi Preface 


has been taken to preserve accuracy of statement, to avoid the making of a mere ‘‘ wonder- 
book,’’ and to keep the volume in touch with the better sources of information. Much of 
it is, necessarily, a recapitulation of elementary facts; it is frankly a book for ‘‘the be- 
ginner’’; and yet I have worked in the conviction that the beginner is peculiarly entitled 
to soundness and sobriety of statement. The facts themselves are sufficiently interesting, 
without embellishment or exaggeration. 

How much of success has been attained I cannot judge. The whole literature of the 
subject is so replete with detail that it is impossible wholly to eliminate the factor of error. 
Those who know the subject best will, therefore, be the most generous in judgment; for 
these will know, as none others can, what to the author must be the labor-cost of even so 
elementary an undertaking. 

Many of my obligations are expressed in the brief bibliography at the close of the 
volume. The data as to star magnitudes are, for the most part, from the Revised Harvard 
Photometry (1908). For the measures of double stars, for the magnitudes of components 
not given in the Harvard Photometry, and for much other technical information I am in- 
debted to the Sternverzeichnis of Ambronn (Géttingen, 1907). The results there given are, 
of course, largely compilations from Burnham and from other sources, but the volume 
is none the less admirable as a general summary of stellar information. For the data as to 
the distances of the stars I am indebted to the List of Parallax Determinations by Kapteyn 
and Weersma (Groningen, 1910). The plan for showing the stars in a dark sky, with 
key-maps to the same scale, was first suggested to me by Miuller’s Adlas to his Kosmische 
Physik. Supplementing this general method with certain features suggested in The 
Midnight Sky (by Dunkin of the Greenwich Observatory, 1872), and adding certain 
practical features gained in the personal experience of observation, I have tried to se- 
cure a composite result—a result based upon sound precedents and yet representing 
a real advance in the mapping of the skies for popular use. Of the specific plan and 
method of the maps I have written at length in the introductory pages. 

In closing these brief acknowledgments I must record my thanks to the Yerkes Obser- 
vatory, to the Mt. Wilson Observatory of the Carnegie Institution, to the Lick Obser- 
vatory, and to Dr. Percival Lowell, Director of the Lowell Observatory, for the use of 
photographs. I wish also to thank my friend, Mr. Burtis B. McCarn of Chicago, for 
much admirable work in the drafting of the maps; and finally I would say that in the 
arrangement, plotting, and articulation of the maps and diagrams, and in the assembling 
of the technical data, I am indebted to the codperation of a devoted hand to which I am 
not permitted to make public acknowledgment, but to the generosity of which I am 
something more than grateful. 

K. McK. 


New York City, 
January, I9I2 A.D. 


II. 


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Contents 


PAGE 
INTRODUCTION ; : : : : : : : ‘ I 
OUR HERITAGE IN THE STARS — THE SKY AND ITS MAPS. 
OBJECTS TO BE SEEN. I.—THE STELLAR WORLD : : ; : 9 
WHAT ARE THE STARS? —-STAR MAGNITUDES AND STAR SYMBOLS— THE DOUBLE STARS—THE 
VARIABLES — STAR COLORS AND STAR CHARACTER — THE CLUSTERS AND NEBUL&. 
LEARNING TO OBSERVE . Z : 2 ; : : ae 2 
FOUR KEY-GROUPS — LOOKING NORTH, ALL SEASONS ——- LOOKING SOUTH, NOVEMBER TO APRIL — 
LOOKING SOUTH, APRIL TO AUGUST — LOOKING SOUTH, JUNE TO NOVEMBER. 
STAR-Maps FOR ANY YEAR . : , : 30 
THE USING OF THE CHARTS, SOME PRACTICAL SUGGESTIONS — A TIME SCHEDULE FOR ALL HOURS — 
NIGHT-CHARTS AND KEY-MAPS, TWENTY-FOUR PLATES WITH ACCOMPANYING TEXT. 
OBJECTS TO BE SEEN. II.—THE SOLAR SYSTEM . : ' ; RO? 
THE SUN — THE MOON, WITH FOUR PHOTOGRAPHS AND THEIR KEY-MAPS — THE PLANETS, AND 
TABLES FOR FINDING THEM — COMETS AND METEORS, 
SOME INSTRUMENTS OF OBSERVATION : : to MSW 
THE OPERA-GLASS— THE FIELD-GLASS — THE HAND TELESCOPE, OR SPY-GLASS — THE ASTRO- 
NOMICAL TELESCOPE, SELECTING IT AND USING IT — THE VALUE OF LOW POWERS — HINTS FOR 
THE BEGINNER. 
AN OBSERVER’S CATALOGUE OF TELESCOPIC OBJECTS : s 7 iets 
STATISTICAL TABLES OF STAR DISTANCES, ETC . ; : ; : , we 
INDEX : ; . ; : : : : : ‘ F ae 47 


X. ADDITIONAL MAPS; THE CELESTIAL SPHERE NORTH AND SOUTH 


vu 





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A BEGINNER’S STAR-BOOK 


1. Untroduction 


Our HERITAGE IN THE STARS 


My first impulse was to name this book “The Stars—with Astronomy left out.’”’ I 
have not done so, and yet such a title would represent no serious misstatement of its 
purpose. It is a purpose sincerely consistent with the most grateful estimate of astronomy 
as a science. But just as there may be a pleasurable familiarity with the flowers, without 
any very great knowledge of botany, so there may be a pleasurable knowledge of the 
stars without any very large acquaintance with the technicalities of astronomy. Indeed 
the pleasure of the stars may be the pathway to their science, just as a homely, familiar 
knowledge of the flowers will often lead to an understanding of their botany. 

Such a suggestion is in harmony with the better and happier educational methods of 
our time. We are learning to awaken and develop the natural enthusiasms which make 
the true geologist by taking our classes into the hills and the fields; we are teaching natural 
history by seeking to interest the beginner in the animal life about us. In almost every 
department of education we are now trying to go, first of all, to the objects themselves; 
and we are seeking to build up our knowledge less upon a basis of discipline and convention 
and more upon a basis of interest. And yet in astronomy we still find, altogether too 
often, that the pupils in our schools are compelled to busy themselves with the angles and 
circles of the celestial sphere, with the grim mystery of solstices and nodes, before they 
have been brought face to face with the friendly realities of the sky. 

So is it, also, with the general reader of adult years—for whom this book is more es- 
pecially intended. Even our more popular manuals of astronomy too frequently assume 
that the mathematics of the science are already known,—or, if not already known, must 
necessarily be learned. There are many pathways to the pleasure of the stars. To the 
minds of some the way of mathematics may be, instinctively and naturally, the best 
method of advance. Some of the greatest of astronomers—such as Newton himself—were 
primarily mathematicians and were never very great observers. But for most of mankind, 
observation in its most elementary sense—observation finding its primary impulse in the 
simple pleasure it awakens—must be the method of approach. The purpose of this book 
is, therefore, to take the reader directly into the presence of the stars, showing the beginner 
when to look and where to look, and what there is to see. 

As knowledge is increased, the field of interest is enriched. While the volume is an 
attempt to begin with the beginner, it also attempts to go on with him. It seeks to pro- 
vide, at least in some measure, for the larger interests that may be awakened. Without 
intruding into the field of theoretical astronomy, I have thought it well to add, in the 
chapter devoted to each subject, such general information as may help to quicken and 

I 





2 H Beginner’s Star-Book 


develop the broader knowledge of the observer. These facts are stated in untechnical 
language, and they are intended to be suggestive rather than complete. In the hope, 
moreover, that the reader may be moved to seek elsewhere for fuller materials, the names 
of a few useful books—some elementary and some that are more technical—are added at 
the close. But sufficient information and guidance are given in the present volume 
to advance the beginner at the very opening of his study to a use of the simpler optical 
instruments, and to direct him at once to the more Mteresting telescopic objects. 


THE UNAIDED EYES 


Much can be done, and much known, without optical aid of any kind. The science 
was founded by men without telescopes. The Egyptians, Hebrews, and Arabs had none; 
Copernicus had none; Kepler, even, had none—or had none till after he had made all 
his larger contributions to astronomy. And yet an elementary knowledge of the familiar 
stars—knowledge easily within the grasp and interest of the average child of twelve—is 
wholly left out of the lives of multitudes of men and women largely because it is assumed 
that in order to know the stars they must have elaborate instruments. There are many 
who may well send up Carlyle’s oft-quoted plaint: ‘‘Why did not somebody teach me 
the Constellations, and make me at home in the starry heavens which are always overhead 
and which I don’t half-know to this day?”’ By reason of such ignorance the world is, 
I think, the poorer. 

For, after all, astronomy is not the most important thing, by any means, that the 
stars have to teach us. To know them is to know a world that is intrinsically beautiful, 
a world full of the immense and the illimitable—and yet not vague, inchoate, confused, 
but coherent, and of exquisite precision in the definiteness and consistency of its order. 
Really to dwell in such a world and to dwell in it intelligently and responsively is to be 
more completely ‘‘at home’ within the universe in which we live,—for Carlyle’s phrase 
is just. And if there be ‘‘no time’’ in our hurried and busy generation for a sense of the 
mystery and order of the stars, is not this itself one of the reasons why we should take 
time for them, and for the healing power of those silences to which they league their un- 
ceasing invitations? Our life, just now, is not too rich in imagination, nor too deeply 
moved by the sense of reverence or the touch of wonder. 

First of all, therefore, and as a basis for all that any optical instrument may contrib- 
ute, I have attempted in this little book to bring the reader to such a knowledge of the 
stars as may be acquired by the employment of the unaided eyes and the average mind. 
But both—the eyes and the mind—must be employed. Not that the task is at all exacting. 
Indeed I am familiar with no other class of useful and interesting information so quickly 
or readily acquired by the beginner. I am speaking, of course, not of technical astronomy 
but of the stars themselves—their groupings, their movement, their seasons, their individual 
characteristics. But eye and mind must be employed—not disemployed, as is too often 
the habit of those who flit vaguely and absently from topic to topic among the various 
fads of the ‘‘nature-lovers’ ’’ cult,—really seeking anything but nature and loving nothing 
but the vague sense of being ‘“‘broad.’’ Yet fifteen minutes of real reading by day, and 
(even more important) fifteen minutes of attentive looking at the actual sky by night, 
will shortly put the real clues of the subject into the hands of any interested learner over 
the age of twelve. Young people who know their way about the skies as familiarly as 
they know their way to the post-office are not more remarkable mentally than those who 
do not; they are as real as the boy who can easily quote the batting averages of his favorites 


Our heritage in the Stars a 


in cricket or base-ball, or the woman who can quote the prices on the fur coats in the ten 
shops just visited, or the man who has no trouble remembering “‘quotations”’ on ’change. 
It is merely a question of being interested. 


OPERA-GLASS AND FIELD-GLASS 


In learning to identify the star-groups, or constellations, an opera-glass is always 
useful. While not essential, such an instrument is of value partly because it adds greater 
brilliancy to some of the richer star fields, and partly because it will often aid the beginner 
in locating the fainter stars and in more readily tracing the outlines of the constellation 
figures. This is especially true on misty nights. On nights distinctly foggy, waiting is 
the better part of science. The stars will return again; and an optical instrument, from 
the least to the greatest, will not work many wonders in bad weather. 

The advantages of the opera-glass are possessed in even larger degree by the modern 
“field-glass,”” or prism binocular. Many of these, unfortunately, are almost as expensive 
as a telescope, but while lower than a telescope in magnifying power they are extremely 
convenient in size and their uses are more varied. Those who already possess such a 
glass will gain great pleasure from its use at night, and those who do not own either an 
opera-glass or a binocular will find on p. 97 some further instructions as to the selection 
and cost of instruments. 

We cannot say that their use, valuable as it is, is wholly necessary to a pleasurable 
knowledge of the stars. Still less can we say that the occasional use of optical help, 
however great, will ever serve as a substitute for the interested, intelligent use of the 
unaided eyes. Yet as we use our eyes, most of us wish to see better than we do; the 
use of an opera-glass soon makes us wish to use a field-glass or a “‘spy-glass’’; and 
the use of these will soon suggest, at least in many cases, the larger possibilities of the 
telescope. 


THE SMALL TELESCOPE 


The impression that the really fascinating interests of astronomy are solely within the 
scope of large and expensive instruments is quite unfounded. All the characteristic subjects 
of observation are within the scope of simple and inexpensive glasses. It is true that op- 
tical aid, of some kind, is desirable. The almost inconceivable distances of space can be 
partly traversed by our unaided vision, but it is absurd to claim that without optical 
assistance of any kind we can see just as well as though we had a telescope. The glass 
need not be large. It may magnify but fifteen times or twenty times or sixty. But in 
each case there is a gain. Indeed, with a glass magnifying only two times the object is 
brought twice as near. With a glass possessing a magnifying power of twenty or a 
hundred the object is brought nearer by twenty or a hundred times, and, if there 
be sufficient aperture, is made to appear proportionately brighter or clearer to the 
average eye. 

So wide, however, are the reaches of the universe that even such changes do not always 
endow our objects of vision with impressive “‘size.’”’ The largest subjects take on dimen- 
sions that to the beginner seem of very meagre bulk. Yet the real telescope, however 
small, will show—as I have said—the characteristic objects of astronomic interest. It 
may not show all the star-clusters, but it will show enough to illustrate charmingly just 
what a star-cluster is. The small instrument will not show all the double stars or all the 


4 H Beginner's Star=Book 


conformations upon the surface of the moon; but to the real observer it will reveal stars 
of varying colors—double, triple, and quadruple; and it will make the face of our moon 
a spectacle of increasing fascination. Its larger mountains, “‘seas,’’ and “craters,” 
indeed more than two hundred features of its topography, stand out in clear relief. Ob- 
jects such as these, together with the crescent phase of Venus and the four larger satellites 
of Jupiter are easily within the scope of a 2-inch* instrument; and a telescope of 24, 
214, or 3 inches will show these objects—and many others—under still better conditions 
of light and power. The photograph of the double cluster in Perseus shown on the 
opposite page was taken with a large instrument; but the existence of the cluster may 
be detected with an opera-glass, and much of its beauty and impressiveness may be 
caught with even the smallest of telescopes. At a cost of from $20 to $150, according to 
size, quality, and equipment, the average man or woman can command an instrument that 
will open a new world of abundant and varied interest. 


THE SKY AND ITS MAPS 


I once asked an accomplished watcher of the skies how he had managed to begin, 
and to begin successfully. His reply was—‘‘I had a friend.’’ There could have been no 
better answer. 

There is, indeed, no better help toward learning to recognize the stars and the star- 
groups of the sky than the friend who knows and who is able and willing to teach. But 
such a friend is not always present; and it sometimes happens that such a friend, even when 
present, will crowd so much into his occasional opportunities for instruction that the re- 
sulting impression, to the beginner, is bewildering rather than informing. 

In any case, and however deliberate the instruction, a chart or map is always helpful; 
and such an aid is especially important if no friend be right at hand. Here, however, we 
meet one of the real difficulties. The vault of the sky does not appear to us as a flat sur- 
face but as ‘“‘an inverted bowl.’’ Our earth seems to us to revolve on its axis at the centre 
of a hollow sphere, lighted from the sun by day and from the moon and the stars by night. 
As we look away to the horizon, whether toward the north or east or west or south, we 
seem to be gazing not at a flat wall but at concave impalpable surfaces which, bending 
inward, meet at the zenith overhead. 

Now if these northern or western or eastern or southern skies were flat, it would be 
a simple matter to map them precisely as they are. But just because these surfaces are 
not flat but like parts of the inner surface of a hollow sphere, we cannot draw or print 
them on a flat surface without causing a certain amount of distortion in the picture. This 
distortion is not great at the centre of the map, but at the edges we must always remember 
to allow for it in comparing the map with the actual sky. In order to reduce this dis- 
tortion as far as possible I have here abandoned the attempt to present the whole sky in 
a single map. Two maps are given for each “sky,” one showing the stars as the observer 
faces directly north, one as the observer faces south. But where, at the edges of the 
maps, distortion does appear, it has seemed best to face it frankly;—not to ignore it or 
conceal it but to deal with it as inevitable, to point it out, and to show—so far as 
possible—how we may allow for it and correct it. 


* Telescopes are usually classified, as to size, according to the surface diameter of the lens at the large end of the 
instrument. A 2-inch telescope, and a 3-inch, are telescopes in which these lenses are, respectively, 2 inches or 3 
inches in diameter. A 2-inch will bear a magnifying power, for the average eye, of from 15 to 70 diameters; a 3-inch, 
from 25 to 110 diameters. These are low estimates. The trained eye can of course utilize far higher magnifications. 
See, for further practical suggestions, pp. 104, II0. 


REGION OF THE DOUBLE STAR CLUSTER (i, x) IN PERSEUS 
From a photograph taken at the Yerkes Observatory 





6 H Beginner’s Star=Book 


In at least one other respect the system of mapping here adopted will be of special 
service. The reader is provided not only with a series of Key-Maps on the right-hand pages, 
but also with a series of Night-Charts, on the left hand, showing the actual sky, without 
lines or symbols. The observer is thus enabled while looking at the pages of his book, to 
enter more easily into the mental experience of relating the night sky to a printed map. 
This—even where there may be some distortion—is a more important privilege than 
the veteran star-gazer has always realized. 

Usually, the beginner must look at a map in a book, a map somewhat crowded with 
lines and symbols, and then go look at the sky. The sky to which he turns has on it, how- 
ever, no lines, no letters, no symbols. Just because the beginner 7s a beginner, the mental 
experience of relating lines, letters, and symbols to a real sky (and a dark sky at that) 
which has on it no such markings, is wholly new. The task is likely to seem even more 
difficult than it is; and it often proves discouraging. Through the use of the Night-Charts 
here provided, the beginner easily learns, from the Key-Map opposite, how to associate 
the lines and symbols with the uncharted sky. He can enter into this new mental ex- 
perience by easy, deliberate stages and at his own convenience. Having first “‘done it in 
a book,” it will be much easier to do it afterward in the open. And in using the book it 
will often prove interesting to cover the Key-Map witha card, and test, by first looking 
at the Night-Charts alone, just how much of one’s star-lore has been remembered. ‘The 
same general method has been followed with the moon. On the left-hand pages are 
photographic reproductions of the actual moon, on the right-hand pages—drawn to the 
same scale—are the numbered Key-Maps. 

Because the stars repeat themselves, there will be much repetition in the text. 
Because intended primarily for the beginner, these repetitions must extend not only to 
the objects of observation but to methods. The repetition of elementary facts and 
suggestions may prove an irritation to the fastidious, but as the volume is intended for 
use rather than as a book merely to be read, there seems to be no alternative. 

The beginner may at first think that the Night-Charts and their Key-Maps are rather 
full, presenting too many stars and too much detail. They are not fuller, however, than 
the sky. Some books upon the subject do present only one star-group at a time; and some 
—while presenting all the area of the sky—reduce the number of objects in the picture 
by omitting most of the smaller stars. But if we present the sky at all it is best, perhaps, 
to present it just as it is or as nearly so as we may. A few of the smaller stars have been 
omitted, but should we leave out all of the smaller stars we should often have to omit some 
of the most characteristic features of a group; and in presenting only one group at a time 
we should have to omit one of the most interesting phases of the subject—the relation of 
the groups to one another. 

Two additional reasons have seemed to me important: I have wished to make the 
volume not only a good book with which to begin, but, as already suggested, I have tried to 
make it also a book with which to go on. Not that the advanced observer will care to stop 
short of manuals larger and more technical; their use will be both interesting and neces- 
sary. And yet the simpler book, if sound in method, should not be so simple as to be 
outgrown before the aid of more pretentious manuals can possibly be utilized. Secondly, 
the detail of the maps has seemed to me to be justified by the needs of the telescopist. 
It has always seemed to me absurd to declare that the intelligent beginner must postpone 
the pleasure of using a small instrument till he has mastered the constellations. The 
telescope would be used far more largely both in our schools and in private hands if the 
beginner could quickly learn where the objects of interest may be found, and how to point 


Our Heritage in the Stars 7 


the instrument under the guidance of clear maps directly related to the actual sky. Such 
needs, and others of like nature, the drawings of this little volume are intended to meet. 
By placing the general descriptions of the star-groups directly under the Night-Charts on 
the left, and the descriptions of telescopic objects directly under the Key-Maps on the 
right, we are able to introduce the amateur very early in his study both to a knowledge 
of the constellations and to the direct use of the telescope. 

It is not unlikely, however, that the maps will seem, at the first, unduly crowded—in 
spite of what has just been said. The skies themselves are full of variety and detail; 
the subject—to the beginner—is new, its vocabulary unfamiliar, its symbols strange. 
What wonder, therefore, that he cannot “lazy himself into it’? as he might lazy himself 
into anew game. But the subject is not difficult. Its possibilities are quickly available. 
Its rewards are not delayed. They come with the first steps, and with succeeding steps 
are richly multiplied. One suggestion, however, should be kept in mind: ‘‘ Proceed 
slowly, at the first.” Do not attempt too much at once. Get clear strong grasp on what 
you do learn. Take one thing at a time. In such case, each item of progress may be 
made a secure basis of association; group may be added to group, fact to fact, till suddenly 
—as one learner, in delighted amazement, expressed it—‘‘the constellations will seem to 
walk down to you out of the sky.” 

Your landscape here upon our earth may change with each mile of your journeyings. 
Your skies, however, will remain. Whether in San Francisco or New York, whether in 
London or Florence, the same skies, approximately, will arch themselves over you, and 
spread above you “‘the loved familiar roof of home.’’ They will unite you with past ages 
and older cultures, whether Biblical, Oriental, Greek, or Roman, just as they unite you to 
the lands of the present. And while they touch the larger emotions and open broader 
horizons to the mind, the imagination to which they speak is not that vague illusion of 
the inchoate which a superficial hour so often confuses with the splendor of the sublime, 
but the imagination which springs from the evidences of precision and exactitude, from 
the sense of method and the bracing consciousness of law. It is a wholesome world in 
which to think and dwell. 


“Plainness and clearness without shadow of stain! 
Clearness divine! 
Ye heavens, whose pure dark regions have no sign 
Of languor, though so calm, and, though so great, 
Are yet untroubled and unpassionate; 
Who, though so noble, share in the world’s toil, 
And, though so task’d, keep free from dust and soil! 
I will not say that your mild deeps retain 
A tinge, it may be, of their silent pain 
Who have long’d deeply once, and long’d in vain— 
But I will rather say that you remain 
A world above man’s head, to let him see 
How boundless might his soul’s horizons be, 
How vast, yet of what clear transparency! 
How it were good to abide there, and breathe free; 
How fair a lot to fill 
Is left to each man still!” 

MATTHEW ARNOLD: A Summer Night. 


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I. Objects to be Seen: The Stellar World 


WHAT ARE THE STARS? 


ONE will often note in some current ‘‘Almanac”’ the statement that Venus or Mars 
or Saturn or Jupiter is the evening or morning “‘star.’’ The expression, however familiar, 
has led to much misunderstanding. In the strict sense, Venus, Mars, Jupiter, Saturn, 
Mercury, are not stars at all. They do not shine by their own light. They are planets, 
as is our Earth also, shining by the reflected light of the Sun. About the Sun, these, 
together with the other planets, Uranus and Neptune, revolve; and they are—with their 
attendant moons—the most important factors in what is called the Solar System, 7.e., the 
system of the Sun, or the system having the Sun as centre. 

The stars, in the stricter sense, lie far outside this system. Let us note for a moment 
the comparative distance from our Earth of the very outermost of the known planets 
and the very nearest star. The planet at the greatest distance from the sun, and from 
the Earth also, is Neptune, /arger than our globe, but so far away as to be invisible to the 
naked eye. Neptune is 2792 millions of miles away. ‘That seems, indeed, a vast distance. 
Yet the very nearest of the stars proper is more than 8000 times as far, is distant—in 
fact—more than 25 millions of millions of miles. 

If, therefore, some of the stars seem small to us as they “‘twinkle”’ in our night skies, 
it is only because they are so very far away. And if some of them seem large and bright, 
it is not necessarily because they are very near. It is because, although at vast distances 
from our earth and from our whole solar system, they are so immensely great in size. Most 
of the brilliant stars are actually nearer than the fainter, but Deneb,—one of the brighter 
stars in our sky—is also one of the more remote. Nor is Deneb unique. Most of the 
stars are indeed superbly large and brilliant—many of them being far larger and brighter 
than our sun. For our sun itself is a star (strictly, of course, our nearest star), and all 
the stars are suns—suns set so inconceivably far away in space that in many instances 
their radiance comes to us only as a trembling point of light. We have thus answered 
the question, What are the stars? We know them to be suns, suns shining by the intensity 
of their heat. 


STAR DISTANCES 


So far away are the fixed stars that the mile as a unit of measurement becomes almost 
meaningless. Astronomers have therefore sought a longer “‘yard-stick’”’ and have taken 
for this purpose the distance travelled by light—speeding at a velocity of 186,324 miles 
a second or over II million miles a minute—in a year of time. This unit of measure, 
or ‘‘yard-stick’’ of the universe, is called the light-year. The nearest of the fixed stars 
thus far measured is Alpha (a) in Centaurus, not visible from our northern latitudes. 
This star is 4.3 light-years distant. The nearest of all the bright stars visible in Europe 
and North America is Sirius, 8.7 light-years distant. In other words, the light from Sirius 
which reaches our eyes to-night started on its way more than 8 years ago. Or, to state 

9 


10 H Beginner’s StarzBook 


the same fact somewhat differently, should Sirius be blotted out to-night, we should 
know nothing of it for more than 8 years. A table giving the latest measures for about 
50 of the important stars will be found on p. 139. 


STAR MAGNITUDES AND STAR SYMBOLS 


Because some, at least, of the fainter stars are nearer than some of the bright ones, 
and because some of the bright ones are farther from us than many of the faint ones, we 
do not attempt to classify the “‘magnitudes”’ of the stars according to their actual size. 
We base our classifications of magnitude not on the size or nearness of the star in itself, 
but on the relative brightness of the star as viewed from our earth. So careful and exact 
has been the work of astronomers, that every star that our eyes can see, without a tele- 
scope, is not only registered in well-known catalogues and star-maps, but each star has 
assigned to it a specific magnitude based on actual observations made with instruments 
of high precision.* 

Of these, six different magnitudes, or degrees of brightness, are recognized. A sixth- 
magnitude star is barely visible with the unaided eye, even under good atmospheric con- 
ditions; a fifth-magnitude star is a little brighter, and so on till we reach the brightest— 
the stars of the first magnitude. A few of the stars, however, are so very much brighter 
than the average first-magnitude star that decimals of unity, figures lower than 1, have 
been called into use. The star Sirius, indeed, is classified as of magnitude —-1.6, which means 
that it is over ten times as bright as a star of precisely the first magnitude; nevertheless 
Sirius is listed, in a general way, among the stars of the first magnitude. It is thus always 
important for the beginner to remember that the smaller the numeral of classification the 
brighter the star, and vice versa. Of first-magnitude stars there are twenty; a list of them 
will be found on p. 140. 

The making of so brief a list as that on p. 140 will not seem to the beginner to present 
many difficulties, but that all of the stars of the six larger magnitudes should be accu- 
rately listed and classified will seem almost incredible. Their number, as we look upward 
on any clear and cloudless night, will at first seem fairly limitless. Yet, including all of 
the first six magnitudes, there are really only about 5000 such stars—stars visible to the 
unaided eye—in the total sphere of the heavens. As we see only half this number at 
once (for naturally we cannot survey the skies beneath our feet), the number visible at 
any one time must be reduced to about 2500. When we realize moreover—as has often 
been pointed out—that those near to the horizon are largely obscured to us by mists, 
trees, houses, etc., it is evident that the number actually before us at any given hour is even 
smaller. Newcomb puts the total at from 1500 to 2000. The use of a telescope will, 
of course, bring multitudes of others into view. 

Even so small a number as 2000 will doubtless seem, at first, to be so bewildering as 
to make any definite knowledge of the sky altogether impossible save to an observer with 
special gifts of mind or training. But this is by no means the case. If the stars greatly 
changed their position from night to night, confusion would be inevitable. But, though 
making their apparent revolution once each 24 hours, their places 7n relation to each other 
have been practically unaltered for unmeasured centuries. As we watch them, we quickly 
learn mentally to group the fainter ones about the brighter, according to outlines or figures 


* The two most important catalogues of the stars by magnitudes are that made by the Royal Observatory at Pots- 
dam, Germany, and that made by the Observatory of Harvard University, U.S. A. A list of the 70 brightest 
stars is printed on p. 140, showing their relative magnitudes. 


Che Stellar World 


that have descended to us from the past. 


Pe 


Some of these traditional groupings seem to 
us illogical, but inasmuch as an attempt to change them (and to secure agreement as to 


the change) would only increase confusion, they have been retained. 











SPIRAL NEBULA, KNOWN AS MESSIER 51 
From a photograph taken at the Yerkes Observatory 


In one respect, however, a change has already come. The ancient world saw in these 
_groups of stars the figures of birds or animals or mythological heroes. These fancies 
served, for many centuries, a useful purpose. It was possible to designate the location 
of a star, for example, by reference to it as the brightest star in the head of the Dragon, 
or in the left foot of Andromeda, or in the head of Taurus, the Bull. But this method 





12 H Beginner’s Star-Book 


was necessarily crude, and never very accurate. In the seventeenth century (1603), a 
German astronomer named Bayer published a series of star-maps in which most of the 
brighter stars in each group were designated by letters of the Greek alphabet.* Roman 
letters came also to be employed, as well as our ordinary Arabic figures, I, 2, 3, etc., 
so that these shorter and easier symbols have gradually passed into universal usage. For 
readers of this book who may be unfamiliar with the Greek characters I have ventured 
to simplify in two ways the using of these symbols. First the whole Greek alphabet, 
with the names of the letters, is printed on p. 33. As many, however, will not wish to 
trouble themselves to memorize the alphabet as a whole, I have also given in the text 
itself the English names of the Greek letters wherever used—for example, the Beta () of 
Perseus; the Gamma (y) of Andromeda, etc.t Thus, the beginner who has no knowledge 
of Greek will not only be able to follow the notes below the maps in their references to 
the stars, but will soon gain—almost without knowing it—a working knowledge of the 
Greek symbols. 

The old mythological names for the star-groups or constellations are still retained. 
So also we still keep the ancient names for many of the individual stars. But the figures 
and shapes of heroes, etc., are usually so difficult to discern, so many are now quite un- 
certain in outline and without real helpfulness to the beginner, that they are falling more 
and more into disuse. In this book, while some of the more obvious are pointed out in 
the notes, I have frankly omitted them from the maps. Experience has convinced me 
that they are not of serious value in the learning of the constellations and that the effort 
to trace them sometimes withdraws attention from the interest of the stars themselves. 
For the stars themselves, in the light of our modern knowledge, possess an ever deeper 
intrinsic interest. 


THE DOUBLE STARS 


With our earliest use of the telescope, however small, we shall find that we must add 
to the list of the 1500 or 2000 stars visible in our sky.. Not only shall we see many stars 
not seen before, but stars noted quite clearly with the unaided eye will now be seen to be 
two instead of one. Castor, for example, one of the brightest stars in the constellation 
Gemini, is thus found to be a “‘double.”” Each of the components, if these could be set farther 
apart in the sky, would prove bright enough to be clearly seen without opera-glass or tele- 
scope. They are really so near together, that the two stupendous suns look to the unaided 
eye like one star. A magnifying power of 70 will show their separation. The com- 
panion orbs are in revolution about a common centre of gravity; and Castor is therefore 
called a binary. We shall come upon other binaries as we take up the study of our maps. 

We shall find also that not only are some of the stars binary in character but that 
there are cases in which the components are so close together that no telescope will ever 
be able to divide them. The division has been detected by the spectroscope; and these 


* The suggestion had first been made by the Italian, Alexander Piccolomini, in 1559. For all technical purposes 
astronomers now designate the positions of stars by right ascension and declination, the celestial equivalents of 
longitude and latitude, see note 14, p. 32. 

{In many text-books, and in the technical literature of astronomy, the references to individual stars are made 
merely by the use of the Greek letter in connection with the Latin genitive of the constellation name. For 
example, the star Alpha (a) in Lyra, is thus written a Lyrae; Delta (6) in Orion, is written 65 Orionis, etc. 
Knowing that there are many interested students of the stars to whom Latin and Greek fcrms are confusing, I 
have not only included the English names of the Greek letters, but have used English prepositions for Latin 
genitives. We may thus simplify the course of the beginner without sacrifice of accuracy. See also p. 141. 


The Stellar World — 3 


stars are therefore called spectroscopic binaries; see p. 143. Castor—to which we have 
just referred-—is really a quadruple object; for each of the components visible in a small 
telescope is itself a spectroscopic binary. 

There are also triple stars, and quadruples, etc., as well as doubles. Some of these 
are apparently bound together in interdependent systems like the binaries, revolving 
about a common centre; some, upon the other hand, are merely ‘‘optical’’ doubles or 
“optical” triples,—stars not truly bound together, but placed in the same line of sight 
when viewed from our position on the earth. Their apparent nearness to one another 
is wholly deceptive. In other cases, however, the relative nearness of the components 
to each other is so evident, and their revolution about a common centre of gravity is so 
fully proven, that the observation of double stars is one of the most delightful interests 
of the possessor of a small telescope.* Some of these true doubles, as we shall see, are 
sufficiently ‘‘wide”’ to be divided by a field-glass. 

They become all the more interesting when we note that the separate components of 
the double or triple stars are, in many cases, of different colors. In the star marked 
Gamma (y) in Andromeda, for example, the larger component is a golden yellow, the 
smaller a delicate emerald. In that marked Alpha (a) in Hercules, the larger star 
is a light yellow, the smaller component a dark blue; and in other cases, also, the two 
components are of contrasted tints, yellow and white, yellow and green, orange and purple, 
white and gray, yellow and red. In some of the more striking cases the impressions of 
color are illusory, but there are also many cases of true color-distinction. Observers 
are often disagreed as to their impressions—as is often the case in our impressions of color 
in other objects—and there are instances in which the stars seem to have changed their 
colors, somewhat, since the earliest period of observation. The subject is accordingly 
full of interest and charm. In the calm, unhurried watching of a double star through a 
good instrument on a clear moonless night, one has the same exquisite pleasure as that 
awakened by the flash of two contrasted jewels, each enhancing the subtle thrill and radiance 
of the other. The smaller component, as it clings close within the light of the larger, 
will often look like a tiny dewdrop trembling within the splendor of some golden globe. 
The observer knows that he is really gazing upon two mighty suns at so great a distance 
from us that the imagination is utterly inadequate even to its elementary appreciation 
and that these close-bound stars revolve about their common centre probably divided 
by many hundreds of millions of our earthly miles. Yet a night which lies thus about us 
wearing suns for jewels never loses its appeal even for the hardened astronomer. The 
expressions of enthusiasm for the wonder of the stars, of delight in their mystery and charm, 
have chiefly come in every age not from the ‘‘mere amateur’’—as the cynic might suggest— 
but from Kant or Laplace, from Kepler, the Cassinis and the Herschels. 


THE VARIABLES 


In the Autumn of each year, through the hours of the early evening we shall find at 
the northeast (or in Spring at the northwest) the star known to the Arabs as “Algol.” 
In maps of the stars it is usually marked as Beta (f) in the constellation Perseus. (See 
Key-Maps on pp. 47 and 59). Algol shines usually as a star of the second magni- 


* Speaking of Tennyson’s remarkable knowledge of the stars and of the accuracy of his poetic references to scien- 
tific matters, Sir Norman Lockyer says: “‘I visited Tennyson at Aldworth [his home] in 1890 when in his 82d year. 
One of the nights during my stay was very fine, and he said to me, ‘ Now, Lockyer, let us look at the double stars again,’ 
and we did. There was a two-inch telescope at Aldworth. His interest in astronomy was persistent until his 
death.””—Tennyson as Student and Poet of Nature, by Sir Norman Lockyer and Winifred L. Lockyer, London, 1g1o. 


14 H Beginner’s Star-Book 


tude. At regular intervals, however,—and these intervals are so regular that they may 
be predicted to the fraction of a minute,—its light begins to fail. Within 41% hours it 
loses more than half its brilliance. It stays at “minimum,” its point of faintest bril- 
liancy, for 20 minutes; and then, in approximately 3% hours its light again increases 
until it once more reaches the brightness of a second-magnitude star. After remaining at 
its greatest brilliancy for 214 days, its decline begins anew. There are known at present 
more than 1000* variable stars, although the stars of the Algol type are only about 80 
innumber. Most of the variables are too small, however, to be seen with the unassisted eye; 
but some of the brighter of these stars are easily observed without optical aid of any kind. 

The true explanation of the variations in Algol was suggested as early as the 18th 
century, but no final proof of its validity was afforded till the more recent researches of 
Vogel, Pickering, and Chandler. The chief point of interest to the beginner is that Algol 
is attended by a dark companion, the two bodies being in revolution about a common 
centre of gravity or about another body invisible with our instruments. As Algol passes 
behind its dark companion, the dark companion is interposed between Algol and our 
earth. Thus the brighter star is eclipsed by the dark one, and this eclipse corresponds 
to Algol’s period of lowest brilliancy. As the revolution proceeds, the brighter star passes 
from the shadow of eclipse, and its normal brilliancy returns. 

The star known as Mira—marked Omicron (0)—in the constellation Cetus (Key- 
Maps pp. 61, 41) is quite different in type. Its period of change is much longer— 
sometimes 10 months, sometimes I1. It is usually invisible to the naked eye, but at 
intervals of a little less than a year it becomes sufficiently bright to be recognized, gradually 
increasing in brilliancy till it reaches its maximum, and then, within less than 3 months, 
sinking again so low as to be wholly invisible except in a telescope. Its precise 
degrees of brilliance, both at its faintest and at its brightest, are as irregular as its periods. 
At its maximum it shines sometimes as a star of almost the first magnitude, but more fre- 
quently as of the second or third. Atits minimum it falls to magnitude eighth or ninth or 
tenth. Unlike the case of Algol, no adequate explanation of the variations of Mira has as 
yet been found. ‘There are several other types of interesting variables each having many 
representatives, but for these I must refer the reader to the more general text-books on 
astronomy, noted on p. 144. Mira reaches its greatest brilliancy at intervals of 10 or II 
months,—for 1911 in July; for 1912 in June; for 1913 in May, etc. 


STAR COLORS AND STAR CHARACTER 


We have already found, in connection with the double and multiple stars of the sky, 
that the components of such bodies are often different not only in size but in color. A 
little careful attention, however, will show us that color is a characteristic of all the stars, 
whether double or single. At a first view on a clear, moonless night, all may seem alike; 
but closer observation will show that while some are white, some also are yellow, others 
are a deep orange, others red. Says Sir Norman Lockyer: “The stars shine out with vari- 
ously colored lights. Thus we have scarlet stars, red stars, blue and green stars, and indeed 
stars so diversified in hue that observers attempt in vain to define them, so completely 
do they shade into one another. Among large stars, Aldebaran, Antares, and Betelgeuze 
are unmistakably tinged with red; Sirius, Vega, and Spica are of a bluish white; Arcturus 
and Capella show a yellow hue like that of our sun. 


If we include those comprised within star clusters, and not classified individually, the total would be nearer 
4000. Additional variables are discovered each year. 


SPIRAL NEBULA IN COMA BERENICES, KNOWN AS H. V,. 24 


From a photograph taken at the Mt. Wilson Solar Observatory 


15 





16 H Beginner’s Star-Book 


“Tn double and multiple stars, however, we meet with the most striking colors and 
contrasts; Iota (2) in Cancer, and Gamma (y) in Andromeda, may be instanced. In Eta 
(n) of Cassiopeia we find a large white star with a rich ruddy purple companion. Some 
stars occur of a red color, almost as deep as that of blood. What wondrous coloring must 
be met with in the planets lit up by these glorious suns, especially in those belonging to 
the compound systems, one sun setting, say, in clearest green, another rising in purple 
or yellow or crimson; at times two suns at once mingling their variously colored beams! 
A remarkable group in the Southern Cross produced on Sir John Herschel ‘the effect of a 
superb piece of fancy jewelry.’ It is composed of over 100 stars, seven of which only 
exceed the tenth magnitude; among these, two are red, two green, three pale green, and 
one greenish blue.” 

Impressions quite so striking are not within the range of the unaided eye, nor even 
within range of the instruments available to the average amateur, but the varied beauty 
of the familiar star colors as seen in ordinary telescopes will find increasing appreciation as 
knowledge grows and as mind and eye become more practised in the art of accurate dis- 
crimination. As we have already seen, there is much authority for the contention that 
colors other than the various degrees of white, yellow, and red are due to optical illusion; 
but, where—as here—these ‘“‘illusions’’ are permanent factors in our scene, even as viewed 
by the best eyes and the best instruments, they remain for the practical observer as legiti- 
mate impressions. The questions as to how these illusions arise, and as to how they may 
be said to differ from the admitted hues of white, yellow, and red, only add to the interest 
of the subject. 

A star, moreover, is not a timid flame lighted in a chimney corner. We have seen that 
among all the stars visible to the unaided eye from the latitudes of Europe or North 
America, Sirius is the nearest. And of all the fixed stars of the sky it is the brightest. 
Yet as its very light, at a velocity of over 186,000 miles a second, takes more than 814 
years in which to reach us, we are not surprised to learn that it is more than 20 times as 
luminous as the sun. The star Rigel, shining at the lower right-hand corner of Orion, 
see pp. 41, 45, seems not quite so bright. Isit thereforea smaller sun? On the contrary, its 
real luminosity exceeds that of the sun by 8000 times. Why then should Sirius seem the 
brighter? Chiefly because Rigel’s distance from us is so vast that the light from it which 
meets the eye to-night started on its long journey more than 450 years ago, or before the 
birth of Shakespeare.* Betelgeuze, the other first-magnitude star in Orion, is not so 
bright nor so far away—being at a light distance of about 100 years—but, upon the other 
hand, its mass has been conservatively estimated at more than 22,000 times the mass 
of the sun. Bodies so huge in their proportions and so splendid in the energy of their 
effulgence are not easily to be described, either as to their constitution or their color, by 
a simple label. As to each star, the prevailing color may be red like Betelgeuze or yellow 
like our sun, but as we watch it closely we are likely to see the torrential flash and inter- 
play of more varied hues. Such is especially the case with Sirius; so is it also with Rigel 
and Vega and Capella. Indeed, as to the factor of color, we may well say that each star 
is of many stars compounded. And yet each has its own general hue, for each is itself 
and not another. 

Each one of these far off suns, as we come to know it, and to consider not its color alone 
but the factors of magnitude, of motion, of distance,—its place in the sky, its relation to 


* Kapteyn accepts the almost insensible parallax of Gill and Finlay (0.”007), undoubtedly the most accurate 
thus far obtained. See the table of parallaxes and star-distances, p. 139. 
+ Problems in Astrophysics, by A. M. Clerke. A. & C. Black, London, 1903. 


The Stellar World 7 


other stars, the seasons of its rising and setting,—will be found to possess an individuality 
of itsown. We soon come to know it and to count upon its friendly shining. Even though 
we may not always be familiar with the varied facts or discoveries concerning it, its identity 
will become, in instinctive ways, familiar. It is said that an old tailor when testifying in 
court was once questioned as to certain stitches in a coat. ‘‘They are my stitches,” said 
the tailor. ‘“‘How,” asked the judge, “do you know they are your stitches? Are they 
longer than the stitches of others?’’—" No, your honor.’’—‘‘ Are they shorter?’’—*' No, sir.’’ 
“Then how,”’ exclaimed the judge, ‘‘can you claim that they are yours?”’ ‘Do you think, 
your honor,” replied the tailor, ‘that I do not know my stitches?’’ And the testimony stood. 

How seldom, indeed, can we give particulars as to friends that we have known. Was 
the hair dark or blond? Were the eyes blue or gray or brown? Was the mouth small or 
large? We cannot always say. But when we see the face, its identity is clear; we know 
it. How often, watching at dusk when the fainter stars are hid, and looking out to the 
horizon, we see a flash of slender light just at the brow of some far off hill or down an 
opening lane through a neighboring wood,—a star returning at twilight, after a long 
absence. At the moment we may not know it, but at a second look the mind leaps in 
recognition—it is Regulus, or Capella, or Vega, or Antares; old associations throng within us; 
memories of other recognitions, of congenial spirits who with us once watched its rising; of 
changes that have come; of changes that have not come, but that still wait the will and the 
laborsofmen. Thus is it that the return of the stars may be as the greeting of old friends. 


STAR CLUSTERS AND NEBULZ 


While the stars, therefore, possess an individual identity, there are instances in which 
we can know them only in masses or clusters. Just as men and women, however distinct 
they may be in their own personalities, will often seem from the standpoint of a spectator 
to “‘lose themselves in a crowd,”’ so is it with the stars. At certain points in the sky we 
find them gathered so close together that it becomes impracticable to try to distinguish 
them from one another. These dense masses of stars are called “clusters.’? Some of 
these are visible only in a telescope, though the telescope need not, in all cases, be a very 
large one. Two of the most beautiful, however, are visible to the unaided eye; and here, 
at least, not all the larger stars are lost in the mass;—some of them shine out with marked 
individuality. One of these clusters is called the Pleiades and one the Hyades; both 
are in the constellation Taurus, the Bull. In our notes upon the maps (see pp. 40, 46, 58) 
we will indicate their position more precisely. 

The Pleiades* begin to appear at the northeast in our evening skies (8 P. M.) about 
October Ist; and as the stars rise each evening about 4 minutes earlier than on the evening 
before, we shall see them each night at 8 Pp. M. a little farther advanced upon their way. 
In January, at the same hour, we shall find them, accordingly, too high overhead for con- 
venient observation; but by April Ist, we shall again find them conveniently placed for 
observation at the northwest. As the stars make the complete circle of their apparent 
revolution once in every twenty-four hours, we can anticipate this yearly march through 
the months—if we desire—by “watching out the night.”” The sun’s shining will of course 
make them invisible by day, but we may be quite sure that the Pleiades are actually in 


* “ Many a night from yonder ivied casement, ere I went to rest, 
Did I look on great Orion, sloping slowly to the west. 
Many a night I saw the Pleiads, rising thro’ the mellow shade, 
Glitter like a swarm of fireflies tangled in a silver braid.” 
TENNYSON: Locksley Hall. 


18 H Beginner’s Star-Book 


our sky—at all seasons of the year—about 16 hours out of every 24. The watching of 
such a group for a few nights, not out of a window but under the actual sky, will, in itself, 





LARGER STARS IN CLUSTER OF THE PLEIADES 


(For view at culmination, the side to reader’s right should be held downward) 


From a photograph taken at the Yerkes Observatory 


prove a good beginning in astronomy and will do more to make clear the apparent motion 
of the stars than any amount of theoretic description. (See also pp. 22 and 24.) I say 


Che Stellar World 19 


“‘apparent’’ motion, because of course the movement of the stars, in the sense in which 
I have here employed the word, is not veal. It is our earth that really moves. 

Let us assume that about October Ist we are looking at the northeast (nearer east 
than north), and that at 8 P. M. we discern the five or six brighter stars of the Pleiades just 
rising above the horizon; at 9 Pp. M. they will be higher still. Indeed, if the horizon is shut 
off by high woods or tall buildings, or by clouds or fog, we may have to wait till Io Pp. M. 
before we can get a good look at them. At corresponding hours on November Ist or Decem- 
ber Ist they are, of course, higher up. See alsc, p. 134. 

To the average eye, under fair conditions, five or six stars in the Pleiades can be seen: 
under especially good conditions, seven. An abnormally good eye can see from eight to 
ten. With the use of an opera-glass—the average opera-glass magnifies about 3 diameters 
—as many as twenty can usually be counted. The use of a modern prism binocular, 
magnifying from 7 to 10 diameters, will reveal more than fifty; a small telescope 
will add many more; a large telescope will add almost a thousand; and, finally, the camera 
will bring the total to nearly 2500—for, inasmuch as the photographic plate is more 
sensitive than any eye, the camera when adjusted to the telescope will reveal many stars 
that are beyond the reach of any instrument employed without photographic aid. No 
instrument gives a more beautiful representation of such a cluster than the small telescope 
with a low-power eye-piece. 

The use of low magnifying powers in the observation of clusters and nebulz is essen- 
tial, as will be more fully set forth hereafter. Other clusters will be indicated in 
direct connection with the maps. The location of the double cluster in Perseus, of the 
“‘Bee-hive’’ in Cancer, and of several others—if the night be moonless and very clear— 
can be made without optical help, but there can be little appreciation of their real beauty 
without the aid of a field-glass, or a small telescope; though even an opera-glass—especially 
when brought to bear on some of the coarser groups—is no mean assistance. We may say, 
indeed, that the whole Galaxy or “Milky Way” is in one sense a cluster. Spanning the 
sky ‘‘as a beautiful belt of pale light’’ it makes—when the moon is not shining—one of 
the most marvellous fascinations of asummer evening. Turning an opera-glass or field-glass 
upon it, we discover that it is not a mere waste of glowing cloud but that it is composed of 
thousands upon thousands of stars—stars that seem small because of their great distance 
from us, but which are, in many cases, far larger than our sun. The telescope, as we shall 
see in our study of our Key-Maps, will show that certain sections of it are peculiarly beautiful 
and impressive. 

The nebula is sometimes found in connection with the star cluster, as in the Pleiades 
themselves, but it is often found apart, and it is not strictly star-like in composition. 
Even when associated with such a cluster as the Pleiades the nebulous matter may be very 
faint—beyond the reach of average telescopes—and yet the stars which it enfolds may be 
large and bright. To use an imperfect illustration afforded by other conditions, we may 
say that a nebula looks as though it might be a tiny isolated patch of the Milky Way, but 
in its structure and composition it is gaseous. Sometimes this filmy mass is oval, some- 
times quite irregular, in form; sometimes it will seem to throw out wisps and streamers 
of effulgence, or, again, as shown in the illustration on p. 8, it will seem to us like the 
long and shelving undulations of a thin cataract of light, as it slips from star to star in its 
shining fall through space. 

Some of the most remarkable nebule are spiral in form, and their luminous gases seem 
charged with star-like condensations, though no telescope—however great—has ever 
resolved these points of condensation into true stars. Some astronomers regard the 


20 H Beginner’s Star-Book 


nebulz as stars in process of formation, others regard them as stars in process of dis- 
integration. In certain cases the nebulz seem to be involved in a vast whirlpool 


THE GREAT NEBULA IN ANDROMEDA, MESSIER 31 
From a photograph taken at the Yerkes Observatory 


motion, throwing off their streams of light and matter as a whirlpool in a flood seems 
to throw off its frothing waters from its centre. But so great is their distance from 





Che Stellar World 21 


us or so inconceivable their magnitude that we have caught as yet no visual evidence 
of change. 

The nebulz, however, are not brilliant objects in small instruments. They are dis- 
appointing except to those fortunate enough to command facilities far beyond the range 
of the average purse. And yet it is of interest to get such glimpses of them as we may, 
even if we may not be able to command an impressive view of them. For even the 
highest optical aid can do little more than afford a suggestion of the facts. The longer 
diameter of the great nebula of Andromeda is more than 500,000 times the distance which 
divides our Sun from the Earth; p. 118; and light, speeding from end to end of this mass 





THE GREAT NEBULA IN ORION 
From a photograph taken at the Yerkes Observatory 


at more than 186,000 miles a second, must take eight years in which to complete the jour- 
ney. The mere observation of such an object is worth while, however inadequate our 
view of it; and something of the beauty of at least one of these mysteries of the sky— 
the great nebula of Orion—is, as we shall see, within the range of our smaller instruments: 


‘‘a single misty star, 
Which is the second in a line of stars 
That seem a sword beneath a belt of three. 
I never gazed upon it but I dreamt 
Of some vast charm concluded in that star 


To make fame nothing.”’ 
TENNYSON: Merlin and Vivien. 


Tif. Dearning to Observe: four Rey-Groups 


BEFORE taking up the larger maps the beginner will find it helpful to study the simple 
outlines of two or three of the smaller groups. The stars that I have chosen are not in 
all cases complete constellations but conspicuous groups that are easily and quickly identi- 
fied. By first learning to distinguish these, the task of learning to identify other groups 
is made easier and simpler. These key-groups become “ guide-posts.”’ 

They also serve another and more important purpose. Drawing them—as we shall 
try to do—in closer relation to our actual horizon than is possible with the larger maps, 
we can perhaps see more clearly just how these star-groups look, not only at their highest 
apparent altitude, but when they are rising and setting. With the star-groups toward 
the north, in the neighborhood of the pole, the problem of life-like drawing is quite simple. 
First of all, therefore, let us take the familiar ‘ Dipper,’’—sometimes, in England and 
Canada, called the ‘‘ Plough.” 


LOOKING NorTH—ALL SEASONS 


The seven stars which form the ‘“‘Great Dipper” are always in our northern sky. 
That we do not see them by day is wholly due to the fact that the daylight hides them.* 

The Sun is so much brighter than any of the stars that, whenever its light is in our 
sky, the stars are blotted out. But toward the day’s close—if the air is clear—we can 
begin to see the brighter stars, and as the night comes on we find that the stars have been 
above us and about us all the while. As we watch them we soon see that they, like the 
Sun, seem to move from east to west; taking about 24 hours to complete their round. 
This—as in the case of the Sun—is, however, only an apparent motion. And there is 
another apparent motion of the stars,—that which brings us the star-changes of the 
seasons. In each case, that which really moves is, of course, the earth. One of these 
movements is that of the earth through its orbit round the sun; the other movement— 
on which we here dwell—is the earth’s rotation on its axis. 

We know that as we sit in our car in a railway station it will sometimes seem to move 
when that which moves is not our train at all, but the train just outside. So as our earth 
turns on its axis once in each twenty-four hours the stars themselves do not revolve, but 
they do seem to revolve within this period of time. The axis on which they seem to turn 
will thus coincide, of course, with the axis of the earth—except that this axis will be longer, 
and its ends will seem to extend outward through the stars to north and south. 

Just as the north pole of the earth, for example, is the “‘top point’’ of the earth’s 
axis (a point, like the centre of a wheel’s hub, which seems not to revolve, but 
round which the earth turns) so is it with the apparent wheel of the stars. Its central 

*“FEarth’s dark forehead flings athwart the heavens 
Her: shadow crown’d with stars—and yonder—out 
To northward—some that never set, but pass 


From sight and night to lose themselves in day.” 
TENNYSON: The Ancient Sage. 


22 


Learning to Observe 23 


hub is thus at a point in the sky corresponding to the pole of the earth. If we can find 
this hub we may be sure that at this point there will be no motion of the starry sphere; 
that round it the other stars will seem to turn; that as we come nearer to it their circles 
of revolution will grow smaller (just as the circles of revolution in a wheel grow smaller 
as we look closer to the hub) until, at the pole itself, there will seem to be no motion at 
all. This will all be clear to us as we watch the movement of the Great Dipper. 

Let us assume, for example, that on November 20th (a few days earlier or later will 
make little difference) at about 8 Pp. M. we are looking at the northern sky. At 8 P.M. on 
that date the Great Dipper will be found due north in the position marked A. You will 
see that it is low down, near the horizon, and that the stars marked Beta (f) and Alpha (a) 


a BR 


Coolers 
oD The Pole Star 8B 


FOUR POSITIONS OF THE DIPPER 


are pointing upward toward a bright star located about midway between the horizon and 
the zenith (the zenith is the point directly overhead). This star is called ‘‘Polaris’’ or 
the Pole Star. 

If you will look northward again in a couple of hours you will see that the Dipper has 
moved. You will find it passing on its way from position A to position B. You will note, 
however, that no matter what its position, the stars a and # are still pointing toward the 
Pole Star. You can see the Dipper advance from position A to position B in about 6 
hours, if you care to maintain your watch so long. In six hours more you will find it very 
high up, at position C. It will then pass to position D, and thence to position A again. 

And you can see it pass through all these positions without sitting up any later, if you 
should prefer to look at it—through the course of the year—for a few minutes at about 
8 o'clock each night. For on each night the stars complete their round just about four 
minutes earlier. They are, so to speak, always “four minutes fast.’ Each night at 8, 
therefore, after November 20th, the Dipper will be a little farther along than position A, 
so that at our chosen hour by February 20th the Dipper will be found not at position A but 


24 H Beginner’s Star-Book 


at position B. By May 2oth, at about the same hour, we shall find it high overhead at po- 
sition C. At the same hour, on August 20th, we shall find it at position D; and at about 
8 p. M. on November 20th, we shall find that it has completed its circle and is once more at 
position A. All this will be made much clearer than it can ever be stated in a book if the 
beginner will take this simple diagram in his hands, turn to the north, and put real eyes 
on the real stars for one or two consecutive evenings. 

But, whether we really observe a little or read a little or do a little of both, there are 
four facts that will soon be quite clear. We shall note, first, that the stars are in apparent 
revolution about a central pole; secondly, that the stars in the Dipper marked Beta (f) 
and Alpha (a)—called the ‘‘Pointers’’—are always pointing in the general direction of 
this pole; thirdly, that the star Polaris—alone among the stars—seems not to move; and 
fourthly, that the polar-point around which the stars revolve must therefore be at, or very 
near, this star. 

The fact is, of course, that the pole is not exactly at the star Polaris. Polaris, however, 
is so near to it that it may fairly be called the Pole Star and, if we could place ourselves 
precisely at our north pole, Polaris would seem to stand almost directly overhead, like 
a tiny celestial capstone to the projected axis of our earth. 

While, therefore, this star also revolves about the pole—the exact pole of the heavens 
being of course only an imaginary point—yet, because Polaris is so very near the pole, 
the circle which it makes, as it revolves, is quite small—so small that, for all ordinary 
purposes, the star seems to stand still. A star placed, however, a little farther from 
the polar-hub will, as the great wheel revolves, make a larger circle; and the farther 
from the pole we look—among our northward stars—the larger will be the circles of revolu- 
tion. Of the two Pointers, Beta (8), of course, will mark a greater circle as it revolves 
than the star Alpha (a). And yet all the stars of our sky that are no farther from 
the polar-hub than the outermost star of the Dipper, can describe their circles of 
revolution without being carried below our horizon. They are always, therefore, in our 
northern skies. 

The stars, however, that are placed somewhat farther from the polar-hub will neces- 
sarily, as the wheel turns, dip below the horizon for a longer or shorter period; and the 
farther they are from the pole the longer must they be below our horizon and absent from 
our skies. These stars, as our earth turns on its axis, will seem therefore to rise and set. 
Moreover, as we come to study them we shall see that our figure of speech must be changed. 
For as we face the north and look at Polaris we are gazing not strictly at the hub of a 
flat wheel, but—as we have said—toward the pole of a hollow sphere, its apparent axis 
the projection of the earth’s axis, and its equator the projection of our own equator. We 
may therefore imagine the spokes of the revolving wheel—as they extend—gradually 
bending inward toward us, and forming the ribs of a vast including globe. We stand— 
inclosed as it were—at the sphere’s centre. 

The circumpolar stars turn with the sphere itself, but as they lie so near the pole, the 
circle of their revolution never carries them out of sight. Sometimes, as we face the 
north, we find the Dipper above the Pole Star, sometimes below it; sometimes it is a little 
to our right, slowly climbing upward as in position B. Sometimes it is a little to our left, 
with the bowl turned downward as in position D, but it is always before us in our northern 
sky. Yet with the sphere’s turning, the stars farther from the pole, like bright points 
fixed on the inner surface of its concave sides—as these arch themselves above and below 
the horizon—appear and disappear according to their hours and their seasons. Let us 
make this still clearer by turning to another of our key-groups. 


Learning to Observe 25 


LOOKING SOUTH—NOVEMBER TO APRIL 


We are now to look at a star-group quite far from the pole. So wide is the circle which 
it makes in its daily revolution that its stars not only dip below the horizon, but are really 
above it for only about 10 hours in the 24. As it is so far from the pole we will face now 
towards the south. On the same evening, November 20th, let us first realize as we face 
southward that we have put the pole at our backs. The east, therefore, will be now at 
our left; the west will be at our right. At 8 Pp. M. on November 20th, the stars of Orion, 
perhaps the most beautiful of the constellations, begin to appear low down in the eastern 
sky. 
By 9 o’clock these stars will probably be clear of the mists that in Autumn so often lie 
at ‘‘the edge of the world’’; and by 9:30 or 10 they will be well placed for observation. 
This group is now, let us assume, at position A, with the three bright stars that pass 
diagonally through the great square, pointing upward;* by 1:30 A. M. it will reach position 
B; by 5 A. M. it will reach position C; by 8 A. M. it will have set. 





THREE POSITIONS OF ORION 


Most of us, however, do not care to watch through a whole night, even to follow the 
march of such a constellation as Orion. We will prefer to follow the other method. Re- 
membering that the stars rise each evening four minutes earlier than on the evening before, 
we can just as well follow Orion through his march across the sky by looking for him through 
the hours of the early evening at successive dates. We shall need more time than one 
night or one week or one month. As Orion comes to position A four minutes earlier 
each night, so it will be four minutes earlier when he reaches position B; and by 8 P. M. 
in January we shall find these stars nearer to B than to A. At 8 in February they will be 
quite at B, and by 8 Pp. M. in April they will be at C. We shall thus have almost six 
months in which we shall find Orion conveniently placed for observation among the stars 
of the early evening. 

This little diagram is placed at this point, however, not only in order that we may 
follow the course of one star-group, but in order that we may also get some idea as to how 
Orion looks as he rises and sets. The impression given in the diagram is not perfect. I 
have already explained that—inasmuch as the stars are not arranged on four straight 


*“’Those three stars of the airy Giant’s zone 
That glitter burnished by the frosty dark.” 
TENNYSON: The Princess. 


26 A Beginner’s Star-Book 


walls but seem to dot the inner surface of a hollow sphere—it is impossible to map them 
perfectly on a flat surface like the page of a book. But through such a diagram as we have 
just made, we can help to bring to ourselves a clearer picture of some of the positions of 
the star-groups that make the circles of their revolution far out from the pole. We can 
see how they slant, or tip, as they rise and set. 

If we attempted in our larger maps to show this slant or tip for every group we should 
have to make a globe. We could not do it well on paper without involving ourselves in 
more technical and practical difficulties than the beginner would care to try to understand. 
This slant or tip of some of the constellations is, on the other hand, very quickly under- 
stood in the light of a little actual observation. Moreover, many of the star-groups show 
little if any distortion in the maps; and as we look farther from the equator and nearer 
to the poles north or south we find it less conspicuous. Let us take, therefore, another 
group. It is Corvus, the Crow (or the Raven); and near it we will place the bright star 
Spica (pronounced Spi-ka). 


spig? 





THREE POSITIONS OF CORVUS WITH SPICA 


LOOKING SOUTH—APRIL TO AUGUST 


Those who have seen the figures of beasts and birds in the star-groups of the sky have 
here found the Raven’s eye and beak in the stars at the upper left-hand corner, the feet 
at the corner just below, the tail at the corner diagonally across from the beak, and a half- 
opened wing at the upper corner to the right. Others have drawn or imagined the Raven 
quite otherwise ;—for example, with the beak low down at the right as though picking up 
a grain of corn. All such “pictures” are interesting or uninteresting—according to our 
moods. Let us find our chief interest, however, in the stars themselves. 

The stars of this little group are not especially bright, but the outline which they present 
is clear and simple. It will give us additional light on the lessons already suggested, and 
we may gain from it at least two other helpful points. 

Corvus rises at the southeast, shortly before the time when we find Orion setting at 
the west. On April Ist at 8 P.M. we shall find it a little above the horizon at the position 
marked A. If we follow it through its whole course in a single night, we shall find that 
by 11:15 P.M., Corvus has advanced to position B and by 3 A.M. to position C,—setting 
about 4.A.M. Or, as we have already explained in relation to Orion, we can follow its march 
across the sky by keeping an occasional look-out for it, from week to week, in the skies 
of the early evening. While at 8 p. M. on April Ist it will be found near position A, it may 
be observed—at the same hour—at position B on May 2oth, and at position C by the 20th 
of July, unless the long daylight of July should then prevent our seeing it. 

You will note, however, how constantly the bright star Spica follows it—how closely, 
in fact, Spica is associated with it in all the positions through which it moves. You will 


Learning to Observe 27 


see, therefore, not only how Corvus helps us to find and identify Spica, but how Spica—one 
of the brightest stars of the sky—will always help us to find Corvus under all sorts of 
difficult conditions of light and air. Spica does not belong to Corvus; it belongs to another 
constellation; yet just as one neighbor’s house may help us to find another, so—in finding 
our way about the sky—there is much good use for neighbor-stars. 

The association of Corvus and Spica in our little diagram will serve, therefore, as an 
illustration of a method, the method of learning the stars and of finding our way about the 
sky by the reference of stars and groups to one another. As the ‘‘fixed”’ stars are not 
conspicuously moving about in our heavens but have retained for ages their relative po- 
sitions in the sky, the practice of connecting them mentally with simple lines of direction 
becomes full of interest and value. When, for example, your attention is once called to 
the fact that a short line from the two upper stars in Corvus will always go straight 
through Spica, the association thus suggested is not likely to be forgotten. In the same way, 
we have connected the Pointers in the Dipper with the Pole Star and we shall also see when 
we come to study Orion more closely that the row of three bright stars running diagonally 
through the centre will always point in one direction towards the superb white star Sirius 
and in the other direction toward the reddish star Aldebaran. 

It is also useful, at times, to have a ‘‘yard-stick”’ in the sky, for we may be told that a 
certain star is this or that number of degrees distant from another star, or that a comet 
on a particular night will be found 20 or 30 degrees distant from the position of the Moon. 
Now I5 degrees is a fairly good yard-stick; and if we can remember that the distance from 
Spica to the near corner of Corvus is just about 15 degrees, that the distance from end to 
end on the shorter side of the great quadrilateral in Orion is also about 15 degrees, and that 
the distance across the top of the Dipper’s bowl is just 10 degrees, we shall soon be able to 
get a very fair idea as to proportionate distances in the sky. While in this book I shall 
make few references to distance in degrees, yet there are times when a general idea as to 
what is meant by such references is of service to us all. I will therefore refer again to 
this subject in now turning to the last of our key-groups. 


LOOKING SOUTH—JUNE TO NOVEMBER 


The star-groups at which we have been looking have been so plain in outline, and the 
relations they suggest have been so evident that I now prefer, in closing the series, to 
take something a little more difficult. I would say, however, as to the whole of this section 
on the key-groups, that if the beginner is not able to ‘“‘make it out”’ at the first or second 
or third attempt, there need be no feeling of discouragement. The stars will be found at 
the times and places given them in the series of Night-Charts and Key-Maps; their direct 
observation is not dependent on an understanding of the ‘“‘why and how” of their move- 
ments. The more we can understand, the greater our pleasure is likely to be; but it is 
also true that the more we watch and actually observe, whether with the telescope or the 
unaided eyes, the more certainly shall we understand. To assume, however,—as is so 
often done—that we cannot find pleasure and interest in the stars till we can clearly appre- 
ciate the theory of their motion is as absurd as to claim that we cannot enjoy a landscape 
or a sunset till we can explain the how and why. 

As the month of June begins we shall find at 9 P. M. as we face southward that the bright 
star Altair and its two companions are rising on the left. As the stars rise higher and as 
the mists along the eastern horizon are left behind, they form a small but striking group. 


28 H Beginner’s Star=Book 


The lowest star is not so bright as either of its companions, and yet—if the night be clear— 
these three almost equidistant points of light form one of the finest landmarks of the 
Summer sky. 

By 9 P.M. on June Ist we shall find Altair at position A; at position B by 12:30 A.M.; 
at C by 4 A.M.; at D by 7 AmM., though lost in daylight. Or, preferring to watch it 
marching through the months rather than through all hours of a single night, we may 
observe it during the early evenings of June at position A, during the early evenings of 
July and August as it advances from A to B; and during the early evenings of September, 
October, and November from B to C and from C to D. 

But there are two other groups in the sky, through practically the same hours, to which 
I would now call your attention. Altair and its two companions point—like a straight 
sign-post—in two directions. As they point upward we shall find them guiding us in 
the general direction of Vega, the white splendid star of the constellation Lyra. It is 


oe? iM lea 





g 
u PEF} 
CAPRICORNUS 


FOUR POSITIONS OF ALTAIR 


distant from Altair about twice as far as the distance between Corvus and Spica (now 
southwest as Altair rises) or thirty degrees. As Altair moves toward position B, Vega 
also will be found so much higher in the sky that, as we continue to face south, we shall 
have to undergo some discomfort in looking up at it. But toward this brighter star, 
Altair still makes, with its two companions, the same shining pointer from every position 
and at every hour. 

And this pointer directs us downward as well'as upward. By the time Altair reaches 
position B, we shall see—by looking closely—that there is below it at a distance of a little 
over 20 degrees a dim group of rather small stars,—the constellation Capricornus. It is 
called the Sea-goat, but it looks as little like a goat as Corvus looks like a Raven. Just 
because its stars are not bright and its outline faint, we shall find the direction given us by 
Altair and its companions all the more helpful. Indeed, it is always well, whenever possible, 
to make the brighter groups of stars serve as guides to groups that are more obscure. 
For the obscure groups often possess interesting features even to the beginner. Capri- 
cornus, for example, is one of the constellations through which the planets take their way 
in their march across the sky (see p. 80). It is also interesting to note that the star marked 
Alpha (a) may at first seem to the observer to be single; but even an opera-glass will show 
that it is double, and that still another star is not far distant. 

Here, however,—as with the other key-groups—I have called attention to the group, 


Learning to Observe 29 


not for the purpose of setting forth this or that detail, but in order to illustrate the different 
aspects assumed by certain of the star-groups as they rise and culminate and set. A star 
or a group is said to culminate when it reaches its highest point in its apparent march 
across the sky. 

We have also learned how we may use our knowledge of one group to help us find 
another group; and I have dwelt on all these points here at the opening of this book for the 
reason that each of these suggestions can be taken up and utilized as a method, the beginner 
going much farther than I have here gone—seeing other lines of connection and association, 
and thus building up, through personal interest and initiative, a star-knowledge of his own. 

The associations of such a knowledge will be enriched not only from our study of the 
skies but from the frequent references and allusions of conversation, of science, of letters. 
Words and phrases that were enigmas begin to have a meaning. Similes and metaphors 
that were quite barren become suggestive and fruitful. Much of the scientific news of 
the day and many of the noblest passages in the world’s literature we no longer read with 
a sense of vague helplessness, but with at least some measure of comprehension. We know 
what month the American poet suggests as he refers to the hour ‘‘When Leo sleeps and 
Capricornus wakes’’; and we can tell to what particular season Tennyson had reference 
when he wrote of the evening skies: 


“Tt fell at a time of year, 
When the face of night is fair on the dewy downs, 
And the shining daffodil dies, and the Charioteer 
And starry Gemini hang like glorious crowns 
Over Orion’s grave low down in the west, 
That like a silent lightning under the stars 
She seem’d to divide in a dream from a band of the blest.”’ 


TENNYSON: Maud. 





GIACOBINI'S COMET, DECEMBER 1905, 
See Page 04. 


IW. StareMaps for any Dear 
THE UsING oF NIGHT-CHARTS AND KEY-MaAps. SOME PRACTICAL SUGGESTIONS 


I. The time-table of the maps is exactly indicated under the maps themselves. In the 
fuller schedule shown on p. 35 the black-letter figures indicate the hours directly covered 
by the map; the other figures represent the hours for which the map thus indicated is the 
best approximate help. For intervening dates the map nearest in point of time will prove 
quite adequate. 


2. The notes under the Night-Charts on the left-hand pages will be chiefly used by 
those who wish to employ no optical instrument. The notes under the Key-Maps on the 
right-hand pages will be chiefly used by possessors of opera-glass, field-giass, or telescope. 

3. As the planets are constantly changing their positions they are not given on per- 
manent Star-Maps. On p. 82, fol., the places of the greater planets are indicated month 
by month for each month till the year 1931. Jupiter, Venus, Saturn, and Mars are 
usually such conspicuous objects when above the horizon that the beginner may find their 
march through the constellations a little confusing, for they frequently obscure the outlines 
of the star-groups as found in the maps. Directions for their easier identification will be 
found, therefore, in the special section, p. 80, on the Planets. 

4. The Night-Charts and Key-Maps are thus strictly confined to the stars proper. 
Here are shown their relations to each other and their approximate positions in the evening 
sky throughout the year. The lower border of each map is intended to correspond with 
the horizon of the observer in the latitude of New York or Chicago. Observers as far 
north as London will see at the horizon a little less of the southern sky; those as far south 
as Richmond or Gibraltar will see at the horizon less of the sky to northward, but these 
differences need cause no serious confusion. 


5. The upper border of each map corresponds, at the centre, with the sky overhead. 
The stars here are too high for convenient observation. And the stars at rising and setting 
are also inconveniently placed for observation, for the mists which so often obscure the 
horizon make difficult work both for the eyes and for the telescope. The notes placed 
below the Night-Charts and Key-Maps are chiefly concerned, therefore, with the star- 
groups that are well placed for immediate study. As all the groups repeatedly recur in 
the maps, the method thus indicated involves no neglect of any part of the sky. As 
you face due north or south begin with the sky directly before you. 


6. In each case, however, the map represents somewhat more than the sky straight 
ahead. For each sky the map comes round a little to the right and left. In this way, 
the maps for north and south at any given hour cover much of the east and west also, 
practically presenting together the whole sky. But, as already explained (p. 4), the sky 
is a hollow sphere rather than a straight wall, and so there is necessarily some distortion 
in every map which attempts to put its figures on a flat surface. The beginner will quickly 
learn to adjust himself to this difficulty if he will begin the study of each map—in its re- 
lation to the sky—not at the top or at the sides but at the centre. Look straight away 
to the north or south, and work from the centre outward. | 

30 


The Using of the Charts 31 


7. The presence of the Great Dipper, always in the sky, makes the northern groups 
easier to study than the southern. Moreover the southern groups, as explained on p. 25, 
are absent from the sky for extended periods of time. The direction of their apparent 
movement, from east to west, is shown by the arrows in the upper corners of the maps. 
In the maps of the sky southward these arrows may be taken to suggest not only the general 
direction in which the constellations move but the slant or inclination of the constellation- 
lines, as the star-groups rise and set. This apparent slant or inclination of these figures 
is more clearly and fully set forth on pp. 25, 26, and 28. We see that Orion and Corvus, 
for example, do not march straight across the sky as though the sky were a blackboard 
or a picture gallery but that they follow great curves or circles through the sky’s vault. 
This is true also of Leo: the stars of the “‘sickle”’ rise first and are also the first to set. And 
what is true of these groups is true of all. 

8. Some of the maps will seem to the beginner to be rather full of detail; but as soon 
as the chief groups are learned this impression will pass away. Not that all of the fainter 
stars can be seen when the sky is overcast with smoke or mist. Indeed it is only on the 
clearest nights, when the moon is not shining, that we can get much impression of the 
fainter stars even to the 5th magnitude. This is especially the case in large cities where 
the stars are dimmed or obscured by the diffused glare of many lights. But under good 
conditions the smaller stars do shine forth as “‘the host of heaven’’; and so many of them 
are involved in the outlines of the constellation figures and so many are of telescopic interest 
that their omission would be impracticable. 

9g. In the study of the constellations the habit of frequently copying or drawing the 
outlines of the important groups will be found of great value. No matter how crude the 
results, and even if the observer can do no better than make a hurried sketch on the back 
of an envelope, the effort to record what is seen and remembered will prove a help to memory 
and will contribute to accuracy in observation. Naturally enough, the more carefully 
one draws, the greater the gain. 

10. It should be said that in some of the maps a little more of the sky is included 
in the lower corners than can be seen at precisely the time indicated. For example, 
on p. 40 the constellation Canis Major, at the lower corner on the left, is not wholly risen 
at exactly 8p.M. But as Sirius, its leading star, is then up, and as the whole group follows 
within half an hour, it seemed needless to omit the lower stars and thus sacrifice the use- 
fulness of the map to the literal demands of a time-table. Here, and at other points as 
well, I have ventured to depend upon the common sense of the student. 

II. In using this book out of doors at night it is well to be provided with one of the 
pocket electric flash-lights that are now available almost everywhere at very low cost. 
An ordinary bull’s-eye lantern will do as a substitute. Better, however, than using the 
book out of doors at night—for any book is likely to suffer physical damage from such 
exposure—is the method now suggested: By using the Key-Maps in relation to the 
accompanying Night-Charts, familiarize yourself not only with a few clear groups but 
with the mental experience of relating the lines and symbols to the uncharted sky. Select 
your first groups not at the edges of the diagrams but as near directly north and south 
as practicable. Do not attempt too much at first. Then make your own drawing, on 
as large a scale as you like, of what you may expect to see. Take your lantern with you for 
the reading of your sketch, add to your sketch under the actual sky with your lantern’s 
help, and—returning—compare the result with the maps in the book. The drawing is 
not essential; the method may be easily followed mentally without the drawing or the 
lantern; but care and precision are always worth while, especially at the first. 


32 A Beginner’s Star=Book 


12. Telescopes are classified as to size according to the surface diameter of the lens 
at the large end of the instrument. A 2-inch telescope and a ‘3-inch”’ are telescopes in 
which these lenses are, respectively, 2 inches and 3 inchesin diameter. Further explanations 
of telescopic terms, and directions as to the selection and use of opera-glasses, field-glasses, 
and telescopes will be found on p.97. I have usually thought it well to underestimate 
rather than overestimate what may be accomplished with this or that particular glass; 
the average eye is at first incapable of utilizing the fullest power of an instrument. There 
must be a little experience. The beginner with a 2-inch telescope should therefore first 
find and observe the easier objects suggested for the field-glass; the beginner with a 3-inch 
telescope should first find and observe the objects suggested for a 2-inch; always beginning 
with the low-power eye-pieces. The easier objects are often the most beautiful, and it 
is a good principle to advance from simple tasks to greater rather than to rush to the 
greater, and to advance—only to disappointment 

13. The numbers placed in brackets | ] throughout the notes to the Night-Charts and 
Key-Maps are important. They refer to the items or paragraphs with corresponding 
numbers in the brief Observer’s Catalogue, p. 116. There the reader will also find the 
pronunciation of star-names and fuller descriptions of the constellations, in alpha- 
betical order. Fuller accounts of the nebule and of other objects are included. 
Observers possessing instruments with “‘hour-circles’’ will also find there the positions. 
of the stars by right ascension and declination—the stellar equivalents for longitude and 
latitude. Information is there given as to the position angles of double and multiple 
stars as well as the data concerning the distances and colors of their components. Facts 
of this kind become of increasing interest to the amateur. They are placed in the Ob- 
server’s Catalogue, however, partly to save space and partly because so much detail is 
likely, just at the first, to prove confusing to the beginner. The beginner is thus able to 
use the reference-numbers placed in brackets beneath the maps as much or as little as his 
interest and needs demand. 

14. At the close of this book will be found maps of the two hemispheres of the sky, 
northern and southern. Here the constellations are all shown in their relations to each 
other, and the boundaries of the constellations are clearly indicated. The northern 
hemisphere includes a generous “‘overlap”’ of the southern sky in order that the beginner 
may find on a single chart most of the stars visible in Europe and the United States. 
The lines of right ascension and declination are here indicated: R. A. (or right 
ascension) representing the astronomical equivalent for longitude; S. D. (or south 
declination, sometimes called declination minus) representing degrees south of the 
celestial equator, and N. D. (or north declination) representing degrees north of it. 
The beginner need not go into the subject further in order to use the chart for his 
practical purposes in observation. If he reads in his morning newspaper, for example, 
that a new comet has been seen at a point in the sky described as R. A. xrx hours, forty 
minutes; and north declination (or declination plus) 10 degrees, he has but to turn to 
his map of the northern hemisphere, and note: that as the declination is given as N. 
(or plus) 10 degrees the object is not far from the equator, and slightly northward from it. 
As the equator is clearly shown (see the circle running through Orion, Serpens, Aquila, 
etc.) there only remains to be found the comet’s position in right ascension. The R. A. 
of the stars is indicated by the lines running like the spokes of a wheel from the centre 
to the circumference of the map. These are marked at the border of the map for each 
“‘hour’’ in Roman numerals, from I to xxiv. As the right ascension in this case is 
given as XIx h., 40 m., the comet is evidently in the constellation Aquila, in the general 


Che Using of the Charts 33 


neighborhood of the star Gamma,—that star being not far from the point where a 
line marking R. A. xIx h., 40m., would cross a line marking N. D. 10°. Should the 
reader now desire to study this region of sky in one of the earlier maps he has only to turn 
to ‘“‘Aquila’’ in the Observer’s Catalogue where he will find the Night-Charts and Key- 
Maps in which this general region is mapped for evening observation. If Aquila be not 
then in the evening sky and if the part of the sky in which the comet is to be seen is above 
the horizon only at such an hour as 2 or 3 or 4 in the morning, the observer can easily find 
the equivalent Key-Map by remembering that the Key-Maps with their accompanying 
Night-Charts are just four hours apart. This search among the maps for the approximate 
place of a comet may sound a little difficult in the reading, but the process is really very 
simple ‘‘in the doing,’’ and a little practice will make plain the way. 


15. The English names of the Greek letters are always given in direct connection 
with the letters, wherever the Greek letters are used. Beginners who know no Greek— 
and their number, I regret to say, is growing—will soon learn these letters as they go along, 
without the necessity for learning the Greek alphabet all at once. For those, however, 
who may desire to memorize these characters quickly and as a whole, the Greek alphabet 
is here given in full. The vowel é, where so marked, is pronounced as 4 in bay; 6 aso in 
slow; 6 as 0 in won; u as @ in flute. 

a Alpha; 6 Béta; y Gamma; 6 Delta; e Epsilén; ¢ Zéta; 7 Eta; 0 Théta; z I-éta; 
x Kappa; A Lambda; uw Ma; v Na; & Xi; o Omicron; ALL eNO OG Of Senivina yt bait: 
v Upsilon; g Phi; y Chi; % Psi; w Omega. The pronunciation of the names of the con- 
stellations, etc., is fully indicated in the Observer’s Catalogue. But, as to all technical 
pronunciations, whether of names or letters, it should be clearly understood that these 
are not fundamental to one’s astronomical interest. If any word be used, no matter what 
the language, it is well for us to use it correctly, if we may. But of more importance 
are the stars themselves, and no one should allow ignorance or awkwardness in using mere 
terms, however ancient, to destroy one’s pleasure in the stars. For their clumsy nomen- 
clature the stars are not responsible; nor are the Greeks. Not till the 16th century of 
our era did the stars receive their Greek-letter designations. But an attempt at general 
changes would now bring confusion into the whole literature of astronomy. 


16. Good photographs of star-clusters, nebule, etc., will often prove more impressive 
than views of the same objects through the telescope. The beginner need not be surprised, 
therefore, if his instrument fails to bring to the eye such pictures as this book contains. 
The camera has two advantages over any telescope, however large. First, the photo- 
graphic plate is more sensitive than the eye, and will always reveal more—with any 
particular instrument—than any eye can see. Secondly, the camera, adjusted to the 
telescope, may be made by a clockwork mechanism steadily to follow an object in the sky 
for many hours—thus permitting a very long exposure of the plate. The sensitive plate 
thus receives and retains, not the impression of a moment (as the eye might) but the 
cumulative impression of hundreds of moments. This is of incalculable advantage in 
recording the fainter objects of the sky. The beginner will find, however, that his own 
direct views, through even a small telescope, will possess, in their actuality, a charm which 
no photograph can ever give. The author is under many obligations for photographs to 
the Lick Observatory, the Mt. Wilson Solar Observatory, the Lowell Observatory, Flagstaff, 
Arizona, and particularly to the Yerkes Observatory, Williams Bay, Wis. Most of these 
are acknowledged under the engravings. Where these acknowledgments are not explicit, 


credit should be given to the Yerkes Observatory,—especially for those of the moon. 
3 


H Time Schedule of the Wight-G@barts and ReyzMaps 


SEE THE PAGE OPPOSITE 


IN the table here given the maps which are specially drawn for the dates and hours 
specified are indicated by the black-letter numerals. The schedule also affords, in each 
case, the best approximate map for the other hours of the same evening between 6 P.M. 
and 12 midnight. For example, on the evening of Jan. Ist, there are two sets of maps 
available, those for 8 P.M. on pp. 39 and 41; and those for 12 midnight, on pp. 43 and 45. 
But the latter will also do fairly well on that evening for 10 or 11 o’clock; and the former 
will serve fairly well for 7 or for 9. In the mid-summer months when the long-continued 
daylight obscures the stars till a late hour, the special map for the early evening (for 
6 p.M. on Aug. Ist, for example) will be of little practical value in our latitudes; but the 
special map on that evening for 10 P.M. (for example) will meet every need. While this 
time schedule has particular reference only to the evening hours—showing the scope and 
use of the maps from, approximately, 6 P.M. to midnight—yet an observer who wishes to 
find the proper map for other hours may easily do so by remembering that the interval 
between the maps is just four hours. From one northward map to the next northward 
map is four hours. From one southward map to the next map looking southward is, 
similarly, four hours. The special maps for May Ist, at midnight, by the time schedule, 
are to be found on pages 51 and 53. The best maps for 4 A.M. on May 2d (four hours later) 
would therefore be the maps that follow next in the book,—those on pp. 55 and 57. The | 
page references throughout the time schedule are always to the Key-Maps, the Night- 
Chart in each case being upon the left-hand page directly opposite. These references are 
indicated in the time schedule for the Ist and the 15th of each month; see next page. 
For all intervening dates the nearest map in point of time will be found adequate. The 
maps in which the various constellations are represented in the evening sky may be found 
by reference to the Observer’s Catalogue. In a few instances, in which a large constella- 
tion is divided between north and south, reference to two successive northern or southern 
maps may prove desirable. 


34 


TIME SCHEDULE OF NIGHT-CHARTS AND KEY-MAPS 


The black figures show hours directly covered by maps; the other figures in same division 
show the hours for which the maps thus indicated are the bet approximate help. The 
maps for the sky as the observer faces north are in columns marked N; those for the sky as 
observer faces south are in the columns marked S. For further explanations, see opposite page. 























DATE Hour, P.M. SEE PAGES DATE 
NS 
Jan. TBO. 7; 9, 9 39, 41 Jan. I 
ents 1.7, 8, 9 39, 41 ie iG 
Feb. 17m0;007,..9 39, 41 Feb. I 
Hebaeer5 ).7, 8, 9, 10 43, 45 Feb. 15 
Miareime vere 7, 6, 9, 10 43, 45 March 1 
Marche rs.) 7, 8, 9 43, 45 March 15 
Veet 0, 7,8 43, 45 April 1 
priest 59)-7, 8, 9, 10 47, 49 April 15 
May ie eo, 0, 10 47, 49 May I 
May 15/7, 8 9 47,49 May 15 
June fom On8'7,. 8 47, 49 June I 
imjemer 5 15, QO, 10, II 51, 53 June 15 
July Tae o,) 0, 10 Se, Se July I 
Wolvemd5 7, 3, 9 i ae JalyetelS 
Aug. Tn, 7°. 51, 53 Aug. I 
Puomeet heres, O, 10, II Bhs 7 Aug. 15 
Segal? 7; 8, 9, 10 55,57 Depts msl 
sept. 15 | 7, 8, 9 Soh ay Sept. 15 
Oct iavn0,) 7, 8 statateye Oct I 
Ocvaeeei5.)| 7, 8; 9,;. 10 59, 61 Octee oS 
Nov ie Ose O;. 10 59, 61 Nov. I 
INOVeRE 5) | 7; 8,79 59, 61 Nov. 15 
Dec HO, 75088 59, 61 Dec. I 
eemearl5 li, 6, .9, 10 20 mal Dec. 15 
Dec. 25 6:30, 8230, 9:30 | (ep aa Dece 925 











SEE PAGES 








Hour, P.M. 

Nes 

ss) Wie, BO: 43, 45 
ee aay, fy, 43, 45 
9, Io, II 43, 45 
Ll aloaet 47, 49 
[Oma ae 2 47, 49 
IO, II, 12 | 47, 49 
9, 10, II, 12 47, 49 
Lowel oer 51,53 
LOvmer leer > 51, 53 
LOmel ise o SIG 
OF, He, 1G. 3H 51, 53 
hake VeRO 55, 57 
FOmn Lier 2 55,57 
[Ggetie eel? oa 7) 
9, 10, II, 12 SB} off 
Vien ee 1 59, 61 
itor, Als Fe 59, 61 
TOE tee 59, 61 
OVE LOy uke 59, 61 
ey eee A 39, 41 
Oe lee 2 39, 41 
imey S0qy Ge 39, 41 
Sy dy SG 1 39, 41 
Lil ipy Bare a 43, 45 
10:30, 12:30 43, 45 





35 


SPIRAL NEBULA IN TRIANGULUM, KNOWN AS MESSIER 33 


From a photograph taken at the Yerkes Observatory 





Che Wight-Charts and Rey-Maps 
for Hnyp Dear 


37 


38 A Beginner’s Star=Book 





NIGHT=CHART TO THE SKY AS THE OBSERVER FACES NORTH. 


JAN. 1, 8 P.M., DEC. 15, 9 P.M., DECI a1; 


10 P.M., 


NOV. 15, 11 P.M., NOV. 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 40, 4I. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


Numbers in brackets [ | refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


As we face the north we now find the Great Dipper 
low down in the sky, wheeling slightly upward toward 
theright. Its apparent motion round the pole is described 
on Pp. 23. 

Having found the Pole-star, let us note the group 
called ‘‘the Little Dipper,’ for the Pole-star is at the 
tip of its handle. Some of its stars are quite faint, and 
except with an opera-glass are not easy to see, save 
on very clear nights. The Little Dipper forms part of 
the constellation called Ursa Mrnor [405] or the LITTLE 
BEAR, just as the Great Dipper forms part of a larger 
constellation called Ursa Major [400] or the GREAT 
BEAR. 

In each case the stars convey no clear impression 
of a bear, and such outlines of mythological or animal 
figures are so unimportant that inability to trace them 
need cause no discouragement. The handle of the Dipper 
is the tail of the bear; the bowl is the animal’s hip; the 
ears are at the little group marked Rho (p) and Sigma (¢); 
the nose is at Omicron (0); the forefeet are at Iota (t) and 
Kappa («); the hind feet at Lambda (A) and at Xi (6). 

Let us again follow with our eyes the line from the 
Pointers (a and B) in the Great Dipper to the Pole-star; 
and let us imagine that we are continuing this line in 
the same direction right on across the northern sky. 


Just above this continued line, quite high up, you will. 


see the W-shaped figure which represents the chair of 
CASSIOPEIA [80]. Just below, you will see the fainter 
stars of CEPHEUS [100] making a sort of house-shaped 
figure with roof now pointing to the east. 

Below the group just mentioned we may see the 
head of Draco, the DraGon [160], formed by the 
stars Gamma (y), Beta (8), Nu (v), and Xi (—). To 
the west of Draco, or toward the left, we may note 
CyGnus, the Swan [145]. The stars DENEB [146] 
etc., form, as you will see, the figure of the Northern 
Cross, or, if we wish to find in the same stars the figure 
of the flying swan, the head will be at Beta (8), the 


tail at Alpha (a), and the tips of the wings at Delta (8) 
and Epsilon (€). To the left of CyGNus and quite to 
the west you will see DELPHINUS, the DOLPHIN [155], 
with its pretty diamond-shaped figure; and, below, you 
will note SAGiTTA, the ARROW [335]. 

Below CyGnus and the Cross and to the right you 
will find the small but important constellation, Lyra, 
or the Lyre [260]. These stars will soon be setting. 
The star VEGA [261], bluish white, is one of the brightest 
in the sky. Lyra can always be identified by the 
four-sided figure of the small stars Delta (8), Gamma (y), 
Beta (B), and Zeta (¢). Toward a point in space quite 
near to VEGA our Sun, see p. 66, is moving at the rate 
of more than 720 miles a minute, taking with him the 
earth and all the planets of our solar system. So vast, 
however, are the distances of space that only an infinites- 
imal fraction of the journey is traversed in a century 
of time. 

As VEGA sets, you will see far toward your right, at 
the north-east and very low down, the first stars of 
Leo, the Lion [225], rising. You may have to wait a 
few minutes ere you can make them out. Of these stars, 
forming—as you see—a figure like a sickle, the brightest 
is REGULUS [226]. Above REGULUs are the faint stars 
of CANCER [50], the CRAB; and the brighter stars of 
GEMINI [185], the Twins, shown more fully in our 
next map. Of Lro we will speak again when the 
whole constellation is higher up and in better position 
for observation; see p. 44. The stars here shown lead 
the way, however, and the figure of the sickle serves as a 
convenient sign of identification. 

The stars of CANCER are not bright, and on duli 
nights they are not easy to find except with an opera- 
glass or field-glass. But on a very clear evening the 
pretty star cluster called PRAESEPE or the BEE-HIVE 
[52], can be recognized like a tiny patch of cloud, even 
with the unaided eye. A telescope of low power will 
show the twinkling of its many suns. 





for Opera-Glass, FieldaGlass, and Telescope 39 


PERSEUS 
@ 
X°%%, 7 é 


PEGASUS 
°2@ 


°7 7” & 
Py [ec 
C B CASSIOPEIA * 
, md 
LACERTA °*~e7 


DEL PHINUS 
Y 

ath 

€ 


SAGITTA 


Star Magnitudes 
@ist @2nd @3rd 94th Sth and under, 
© Cluster or Nebula 


fe) 
1735 en 


ge GEMINI 


CAMELO- 


c Castor @ 
PAROUS 


Pollux 
B 
c 


CANCER \g 


OPraesepe 


As the observer faces Northward, 
the stars al his right are rising; 
those at his left are setting. 





KEY-MAP TO THE SKY AS THE OBSERVER FACES NORTH. 


DEC. 15, 9 P.M., DECwaa, 


10 P.M., 


NOV. 15, 11 P.M., NOV. 1, 12 P.M. 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 40, 4I. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer's Catalogue, p. 116. 


I. FoR OPERA-GLASS AND FIELD-GLASS there are fine 
star-fields through CAssiopErA [80] and CyGNnus [145]. 
Here lie some of the richest sections of the Galaxy 
or Milky Way (see p. 19). We can see that it is made 
up of innumerable stars closely massed together. 

In Lyra [260] the star marked Epsilon (€) can, with 
opera-glass or field-glass, be seen as double. In a tele- 
scope 3/4 in. or over, it will be found a quadruple, or 
double-double [263]. In CyGnus almost ona line between 
Alpha (a) and Delta (8) there are two neighbor stars 
marked Omicron (0) [148] making—with the star 32 
{149]—the centre of a pretty field. Near the foot of the 
cross the little star marked 6—though in another con- 
stellation—is an easy double for a field-glass [426]. 

A field-glass, steadily held, will also divide the stars 
marked Delta (8) and Zeta (£) [266, 265] in Lyra, and Nu 
(v) in the head of Draco [162]. Note with the opera-glass 
the little star marked g near Mizar [4o1]in theGreat Dip- 
per. Itsnameis ALcor [402]. Mizarand ALcor together 
were called by the Arabs ‘‘the horse and his rider.” 


II. WuITH A TWO-INCH TELESCOPE the star-fields of 
CycGNnus and CAsSIOPEIA are even more interesting than 
with a field-glass. For these and all the other objects 
thus far noted use a low-power eyepiece. In addition 
to the above try Beta (B) [262] in Lyra, and also Beta (B) 
in CyGNnus at the foot of the Cross, one of the finest 
objects within the range of a small instrument [147]. 
The colors of the components are orange and blue. 
Farther to the west a pretty double is also found in the 
Gamma (y) of DELPHINUS [157]. 

Turning again to the orth we shall find more inter- 
esting still the star Mizar [401] to which we have 
already referred, in the bend of the Dipper’s handle. 
In addition to the little star ALCoR a two-inch telescope 
will show that Mizar is itself a double star, one com- 
ponent a brilliant white, the other a pale emerald. 
Another, fainter, star is also visible, so that with ALCOR 
four objects appear in the field of the telescope. 


In CEPHEUS note the easy doubles, Delta (8) 
Xi (€) [103], and Beta (B) [102]. The last is the most 
difficult. Toward the right and at the northeast, 
double stars for a two-inch glass will also be found in 
CANCER [50]. Try the stars Iota (t) and Zeta (f) 
[53, 54]. A charming star-cluster will be found here in 
PRAESEPE [52] or the BEE-HIVE. It may be readily 
found by drawing an imaginary line from CAsTOoR to 
PoL_Lux and continuing it downward. The sparkling 
“‘star-dust”’ of the cluster will be found slightly to the 
left of it. 


III. WitTH A THREE-INCH TELESCOPE all the pre- 
ceding objects are, of course, even more available. In 
addition to the preceding, the observer can now try to 
divide Portaris, the Pole-star [406], by using a magni- 
fying power of 75 to 100. The companion is not very 
close; it is difficult to see only because of the dis- 
proportionate brightness of the larger component. 

Other stars for a three-inch telescope are Mu (p) 
[153] near LAcErTA, and 61 [150] as well as 17 
{152] and Chi (x) [151] in CyGNus; Omicron (0) [163] in 
Draco; Alpha (a) [261] and Eta (nm) [264] in Lyra, 
though the former is difficult for the beginner; indeed a 
31% or 4-inch telescope may be necessary. To the 
extreme right, try the Gamma (y) [227] of LEo—a 
much more satisfactory object. This star is a binary, 
the two components being in slow revolution about a 
common centre of gravity. Of the stars of GEMINI 
we will speak on p. 41; and the objects in constellations 
above the Pole we will discuss when they are in better 
position for observation. Of the clusters, that in 
CANCER named PRAESEPE [52], and that marked M 39 
[154] (found by an imaginary line from Beta (B) to 
Gamma (y) in CyGNus, projected onward) make fine 
objects if viewed with a low-power eyepiece. There 
are also beautiful star-fields near the star Gamma (y) 
in CyGNus and near the garnet star Mu (p) [104] in 
the constellation CEPHEUS. 


[ror], 


40 


- 


JAN. 1, 8 P.M., DEC. 15, 9 P.M., DEC. 1, 


H Beginner’s Star-Book 





NIGHT-CHART TO THE SKY AS THE OBSERVER FACES SOUTH. 
10 P.M., 


NOV. 15, 11 P.M., NOV. 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 38, 39. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


As we face directly south, the east is of course upon 
our left hand. The stars that are now moving round 
from east to south present a superb spectacle. In 
ORION [290] note first the two stars of the first 
magnitude, BETELGEUZE [291] and RIGEL [292]. 

The former marks the right shoulder of the giant 
huntsman: the latter his left knee. His head is at 
Lambda (A) and the tip of his uplifted club at Nu (v). 
The three bright stars Zeta (€), Epsilon (€), and Delta 
(8) mark his belt, from which his sword hangs down- 
ward with its tip at Theta (8). 

To the left of ORION lies the dim group MONOCEROS 
[270] or the UNICORN, so unimportant that the beginner 
may well omit it till other groups are learned. Higher 
up are the stars of GEMINI, the Twins [185]. The heads 
are marked by CAsTor [186] and PoLLux [187], named 
from the devoted comrades of the ancient myth. 


The three bright stars of ORION’s belt, running diago- 
nally through the oblong figure which marks his body, 
will point us upward toward the red star ALDEBARAN 
[381] and, still farther on, to the PLEIADES [382], the 
most beautiful of the star-clusters. Near ALDEBARAN 
is another cluster called the Hyapes [383], not so 
thickly massed but almost as interesting. Both these 
clusters are in the constellation Taurus, the BuLL [380]. 
ALDEBARAN is the Bull’s red eye, the nose is at Gamma 
(y), the horns stretch away to Zeta (¢) and Beta (8). 
The imaginary figure of the Bull, as with that of 
ORION, is incomplete. 

Again taking our direction from the line of OrION’s 
belt we find it pointing us in the other direction to 
Sirius [66], the brightest of all the stars,—supposed to 
mark the eye in the constellation, CANis Major, the 
GREAT Doc [65]. The dog sits upright with forepaws at 
Beta (B), ears at Gamma (y) and his hind feet at 
Zeta ({). To the right of these stars and a little lower 
down is CotumsBa, the Dove [125]; and a line from 
this group drawn through Sirius and carried onward 


will bring us to CANIs Minor, the LITTLE DoG [7o]. Its 
stars form no outline of a dog; but among them is 
Procyon [71], a fine first-magnitude star. 

To the right of Strrus and just below ORION are the 
stars of Lepus, the HARE [240], and to the right of 
Lepus stretches the long line of EripANus [175], the 
RIVER, taking its rise near RIGEL. Returning now to 
Taurus, we find that the triangular figure which has 
its apex at Gamma (y) points us downward to the 
huge constellation of CETUs, the WHALE [110]. For 
MirA, see p. 14. Above CETUus stretch the dim stars of 
Pisces, the FIsHEs [320], starting from the point at 
Alpha (#) and forming to the westward a pretty 
chaplet of small stars at Theta (8), Lambda (A), Gamma 
(vy), etc. Except on very clear nights some of these are 
not easily found without an opera-glass. 


To the right of the PLEIADEs lie the three bright stars 
that mark the small constellation of AriEs, the RAM 
[30]; and above ArRIEs shines the three-cornered figure of 
TRIANGULUM, the TRIANGLE [395]. Both groups are 
now too high for convenient study; but see p. 55. 

In now looking to the right to the great square of 
PEeGaAsus, the WINGED Horse [301], it will help us to 
assume that the upper corner of the map comes in 
toward us a little and that all the lines slant somewhat 
downward as indicated by the arrow in the corner; 
see p. 4. Far to the south-west, AQuarRius, the 
WATER- BEARER [15], is setting, the mouth of the 
water-jar being marked by the little Y-shaped figure at 
Gamma (y). Still further to the southward lies Piscis 
AUSTRINUS, the SOUTHERN FIsH [330], not to be confused 
with Pisces, the FIsHEs, to which we have just referred. 
The mouth of the Southern Fish is marked by FOMALHAUT 
[331], a star of the first magnitude. It is not so bright 
as SrRIUS or RIGEL but a welcome object in this vast 
region of less brilliant sky. It sets, in the latitude of 
New York, just as Sirius rises. In the latitude of 
London it sets a little earlier. 


for Opera-Glass, fField-Glass, and Telescope 4I 












PERSEUS 
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oe“ AURIGA ge iS 


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CAMS 


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eo 6 





MIONOCEROS 







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Star Magnitudes ‘s e° 
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PEGASUS 







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@@lomalhaut 


a 
SCULPTOR As the observer laces Southward, 
ar the stars at his lett are rising; 
P™ | those at his right are setting. 


KEY-MAP TO THE SKY AS THE OBSERVER FACES SOUTH, 


JAN. 1, 8 P.M.. DEC. 15, 9 P.M., DEG. 1, 


10 P.M., 


NOV. 15, 11 P.M., NOV. 1, 12 P.M. 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 38, 39. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I. WITH OPERA-GLASS OR FIELD-GLASS examine the 
two star-clusters in Taurus, the PLEIADES [382] and 
the HyaAbEs [383]. The glass will greatly increase the 
charm and the interest of both groups; see p. 18. 
Near ALDEBARAN note the pretty doubles Theta (@) 
and Sigma (©) [386, 389], and below ORION another will 
be found in the Gamma (y) of LEpus [242]. 

A field-glass and sometimes even an opera-glass will 
reveal as a faint cloud of light, or misty radiance, the 
great nebula of OrIoN [294]. It enfolds the little star 
Theta (@), just below Orron’s belt. The existence of 
the star-cluster in Cants Mayor marked M 41 [67] 
and of that in GEMINI marked M 35 [188] can also be 
discerned, though here also a telescope is necessary for 
a really satisfactory view. To sweep with opera-glass or 
field-glass, however low its power, through this whole 
region of sky, especially through Canis Major, ORION, 
and Taurus will bring rich returns of interest and 
pleasure. Except with optical aid the star Mira [113] 
in CETUs is often quite invisible. It is strangely vari- 
able. See p. 14. 


II. WitTH A TWO-INCH TELESCOPE all the preced- 
ing objects are available, and the clusters mentioned 
take on new beauty. Using the eye-piece of lowest 
power, note the general aspect of the Orion nebula 
at the star Theta (8) [294]. Then with a higher 
power, 65 or 70, study carefully the star itself. It is 
a quadruple, two of the components being reddish in 
color, one a pale lilac, and one white. Easy doubles will 
also be found in Delta (8) [293], the top star of the belt, 
and in m [295] just above. Sigma (©) [299] just below 
the lowest star of the belt will appear as a triple. 

In GEMINI the most impressive double star is CASTOR 
[186], but Zeta (¢) [193] and Delta (8) [190] are also 
worthy of note. The latter may prove a little difficult 
for the beginnner. In TAuRUs interesting objects will be 
found in Tau (r) [387], and in Eta (n) [384], the brightest 
star of the PLEIADES; but these are high for present ob- 


servation. There is also an easy double quite near the 
star marked (zo) [388]. In MONOocEROs note the pretty 
triple star marked Beta (B) [271] called by Sir William 
Herschel ‘‘one of the most beautiful objects in the 
heavens.’’ The beginner may be able to see only two of 
the components. Try Epsilon (€) [272] in the same con- 
stellationand thestar marked win ErRIDANUuS [176]. Easier 
doubles will be found in the Lambda (A) [31] and Gamma 
(y) [32] of ARIEs, both stars being of special importance. 


III. WITH A THREE-INCH TELESCOPE first try the 
objects mentioned for the two-inch, using a low-power 
eye-piece and giving special attention to the great nebula 
in ORION [294] and the star-clusters already specified. 

In Orton try Lambda (A) [300], just above and to 
the right of BETELGEUZE; two stars [297] below Theta (8); 
and Zeta (€) [296], the lowest star of the belt. The 
latter is a triple but the beginner may not at first see 
more than two of the components. RIGEL [292] is a 
superb double, the small blue companion being an exact- 
ing test even under fine atmospheric conditions. Easier 
objects for a three-inch instrument are the Kappa (k) 
[189], Epsilon (€) [191] and Nu (v) [194] of Gemini. In 
Pisces, a fine double star will be found in Alpha (a) 
[321]; and a fainter but pretty object in Psi (W) [323]. 

A low-power eye-piece will show the small blue com- 
panion to Alpha (a) [111] in CETUS; and, with an eye- 
piece of higher power, other interesting doubles in 
Cetus will be found in the stars Gamma (y) [112]; 66 
[116] and Zeta (¢) [114]. Farther to the west, in AQUARIUS, 
note another Zeta (£) [17], the star at the centre of the 
little Y which marks the mouth of the water-jar. It 
is an extremely pretty double, the components being 
almost equal in magnitude. 

In this map the track of the planets lies through the 
constellations AQUARIUS, PIscES, ARIES, TAURUS, and 
GEMINI. The approximate positions of the planets 
as they move through the stars may be easily found 
for any month, from the tables on pp. 84, 86, etc. 


42 H Beginner’s Star=Book 





NIGHT-CHART TO THE SKY AS THE OBSERVER FACES NORTH. 


MARCH 1, 8 P.M., FEB. 15, 9 P.M., 


FEB. 1, 10 P.M., 


JAN. 15, 11 P.M., JAN. 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 44, 45. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


We now find that the Great Dipper, in its revolution 
round the Pole (see p. 23), is moving from position B 
and is on its way toward position C. The “pointers,”’ 
the stars Alpha (a) and Beta (B) in the Dipper’s bowl, 
will direct us to POLARIS, or the Pole-Star [406]. This, 
as we have seen, is at the tip of the handle of the Little 
Dipper. These starsare part of the constellation called 
Ursa Mrnor [405], or the LirrLtE BEAR. We have 
already shown, p. 38, how the Great Dipper is part of 
the GREAT BEAR, or UrSA Major [400]. 

On the other side of the pole from the Great Dipper, 
and at about the same distance from POLARIS, are the 
stars of CASSIOPEIA, or the LADY OF THE CHAIR [80]; 
they form a figure like a large W, much spread out. 
Above this striking group shine the stars of PERSEUS 
[305]; and higher still are those of AuRIGA, the CHARIO- 
TEER [35], but at present these are rather high up for 
convenient observation. CAPELLA [36] is a star of the 
first magnitude. 

The brightest star in PERsEus, that marked Alpha (a), 
is not far from the famous variable, ALGOL [307], of 
which we have spoken at length on p. 13. These two 
stars form a right-angled triangle with the Gamma (y) 
[3] of ANDROMEDA just below. Farther to the west lie 
the stars of TRIANGULUM, the TRIANGLE [395], and of 
ArtgEs, the Ram [30]. In the former is found the 
beautiful nebula illustrated on p. 36. ARIES lies in the 
track of the planets. The line in ArtEs from Alpha (4) 
to Beta (B) is now more nearly perpendicular to the 
horizon than can be shown at this corner of the map, 
and the TRIANGLE points more nearly downward (see 
NOLEM A Daal). 

Of ANDROMEDA [1] and PEGAsus [301] we will speak 
again when these constellations are rising, p. 54. We 
can see here, however, that the great square of PEGASUS 
is indebted to ANDROMEDA for one of its corner stars. 
To the eye, the Alpha (a) of PERSEUS seems like a con- 
tinuation of the long line of PEGASUS and ANDROMEDA, 


it being the fifth and last in a bold series of almost 
equidistant second-magnitude stars. The star Beta 
(8B) in PEGAsus is now very low down, but before it 
sets we may note that the imaginary line from Beta (B) 
to Alpha (a) in the Dipper, if continued onward across 
the sky, will come very near to this corner in the square. 


We have already spoken of the stars of CEPHEUS 
[100]; of DENEB [146], the brightest star of the North- 
ern Cross; and of Draco [160], the DRAGON; see p. 38; 
but to the right and at the northeast some new groups 
are rising above the horizon. Very low down is the 
constellation called Bo6TEs, the HERDSMAN [4o]. Its 
leading star, the superb Arcturus [41], may be iden- 
tified by its reddish yellow light. Moreover, we may 
note that if we continue the sweep of the circle rudely 
represented by the handle of the Great Dipper, we shall 
find the handle pointing us to ARCTURUS, just as the 
handle of the Little Dipper will always point us in the 
general direction of CAPELLA [36]. Wespeak more fully 
of AURIGA [35] when more conveniently placed; p. 46. 

Just above BoéreEs at this hour, a little to the left, 
are a few faint stars, two among them marked 72 and 75, 
which represent the constellation CANES VENATICI, the 
HuntinG Docs [60]. They make no outline of such 
figures, but the dogs which they symbolize are supposed 
to be running before the HERDSMAN as he drives the 
GREAT BEAR, UrsA Major, around the Pole. We may 
suppose ARcTuRUus to be in the Herdsman’s belt; and 
we may imagine his head to be at Beta (B), his shoulders 
at Delta (8) and Gamma (jy), his extended knee—as he 
runs—at Eta (mn). But the figure has been drawn in 
many different ways. 

Above the HERDSMAN, and to the right from the Great 
Dipper, is the scattered cluster of small stars called 
ComA BERENICES, or BERENICE’S Harr. For the myth 
associated with this group, see the Observer’s Catalogue, 
under its reference number [120]. We will speak of 
Leo [225] on p. 44, as we look southward. 


for Opera-Glass, fFfieldzGlass, and Telescope 43 








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PERSEUS 
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PISCES 33 


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Star Magnitudes 


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As the observer faces Northward, 
the stars at his right are rising; 
those at his left are setting. 


v7) 
Me 
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r Sond 


KEY-MAP TO THE SKY AS THE OBSERVER FACES NORTH. 


MARCH 1, 8 P.M., FEB. 15, 9 P.M., 


FEB. 1, 10 P.M., 


JAN. 15, 11 P.M., JAN. 1, 12 P.M. 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 44, 45. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I, FOR OPERA-GLASS AND FIELD-GLASS the rich regions 
of PERSEUS [305] and CASSIOPEIA [80] present views of 
great interest and beauty. These constellations lie in 
the Milky Way, and, if the night be clear, they will well 
reward the student. Observe especially the superb 
field of stars near Alpha (a) in PERsEus. Note also the 
“‘sword-handle”’ of the hero, composed of the great 
double cluster marked h-x [309] in our map. It is almost 
on a line connecting the star Eta (qn) in PERSEUS with 
Epsilon (€) in Cassiopeia. Its appearance in a large 
telescope is shown by the illustration on p. 5. 

The existence of the great nebula in ANDROMEDA may 
be discerned, also, but it is not so interesting in a small 
instrument. It forms an irregular triangle with the 
little stars 32 and Nu (v), and is marked M 31 [2]. To 
the eastward, or to the right of the Great Dipper, the 
opera-glass and field-glass may be well employed among 
the stars of CoMA BERENICES [120], or BERENICE’S Harr. 
Among the double stars for opera-glass or field-glass, 
steadily held, are Delta (8) in CEPHEUS [101], Nu (¥) [162] 
in the head of Draco, and 15 [62] in CANES VENATICI. 
Note also the stars Zeta (€) [401] and g [402] at the bend 
of the Dipper’s handle. These are M1zAR and ALcor, 
“the horse and his rider.” 


II. For THE TWO-INCH TELESCOPE there are, first of 
all, the objects just specified. The very lowest available 
power should, of course, be used, in order that the in- 
strument may show a broad field, with the largest pos- 
sible amount of light. A somewhat higher power should 
be employed on double stars. Of objects of this kind 
the star Zeta (f) [401] at the bend in the Dipper’s handle, 
is one of the finest. Another beautiful double for a 
two-inch telescope will be found to the Dipper’s right,— 
the star marked z2 [61] in CANES VENATICI. It was 
named ‘‘Cor CAROLI”’ in honor of Charles II. Near the 
tip of the Dipper’s handle, below and to the left, is a 
group of little stars belonging to BoOTEs, two of which, 
Kappa («) and Iota (+) [45, 46] are easy doubles. Such 


are also Delta (8) [43] and Pi (1) [44] of the same con- 
stellation, though we may wish to wait till they are a 
little higher in the sky. We may next observe the even 
easier double star Nu (v) [162] in the head of Draco; and 
the stars Delta (8) [ror], Xi (€) [103], and Beta (B) 
[102] in CEpHEUS. The last is the most difficult of the 
three. The Gamma (y) [3] of ANDROMEDA is one of the 
most beautiful objects within the range of a two-inch 
instrument. Still further to the westward fine objects 
will also be found in the Lambda (A) [31] and Gamma 
(y) [32] of Artes. On a line through the Gamma (jy) 
of TRIANGULUM to Beta (B) and continued onward, 
is a little star, belonging to ANDROMEDA, marked 56 [5]. 
It is a wide double. On a line upward from Gamma 
(y) in ANDROMEDA to the Beta (B) of PERSEwvs lies a fine 
star cluster marked M 34 [311]. The nebula M 33 [396] 
is not far distant. 


III. WmITH A THREE-INCH TELESCOPE all the preced- 
ing objects, both for the field-glass and for smaller 
telescopes, may well be studied before proceeding 
further. Many of them are important objects for tele- 
scopes of any size, however large. PoLaris, the Pole- 
Star [406], is always an interesting object. The small 
blue companion will now be found slightly upward to 
the right of the larger star. One of the most beautiful 
of the binary systems is represented by Eta (m) [82] in 
CASSIOPEIA. The contrast in colors is very marked. 
As the components are quite near together for a three- 
inch with average powers, much care should be taken to 
ensure the steadiness of the instrument. Iota (+) [83] 
in the same group should be tried also, as well as the stars 
Omicron (0) [163], Delta (8) [166], and Iota (+) [164] in 
Draco. Gamma (y) [165], in Draco’s head, is a little 
more difficult. At the time covered by our next map of 
the northern sky, these stars will be in better position for 
observation. Eta () [308] in PERSEUS should be noted, 
and special attention given to the famous double cluster 
[309] just below. 


44. HA Beginner’s Star=Book 





NIGHT-CHART TO THE SKY AS THE OBSERVER FACES SOUTH. 


MARCH 1, 8 P.M., FEB. 15, 9 P.M., 


FEB. 1, 10 P.M., 


JAN. 15, 11 P.M., JAN. 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 42, 43. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


Looking southward, we find that the constellations— 
TAuRuS, Orton, CANIS MAJOR—so conspicuous in our 
last map of the southern sky, have moved farther to the 
west, or toward the right. But these groups are so 
brilliant that they dominate the scene here just as they 
did in our study of them on p. 4o. 

Canis Major, or the GREAT Doc [65], is before us 
directly to the south. A line through this group, from 
the star marked Delta (8), up through Srrius [66], the 
brightest star of the sky, will point almost directly to 
BETELGEUZE [291], the fine reddish star in the right 
shoulder of OrION [290]. Under the map on p. 40 we 
have pointed out how the stars of these two groups were 
supposed to suggest the likeness of the GREAT Doa, and 
the GIANT HuNTER. If we continue the imaginary line 
from Srrius to BETELGEUZE, and carry it onward, it 
will cross the horns of TAuRus, the BULL [380], which is 
supposed to be charging down upon OrIoN, his fiery red 
eye being at the star ALDEB’ARAN [381] and the tips of his 
horns at Zeta (¢) and Beta (B). 

High above these stars is CAPELLA [36], the splendid 
first-magnitude star of AURIGA, the CHARIOTEER [35], 
and lower down, to the westward, are the PLEIADES 
[382]. Near ALDEB’ARAN shines the more scattered cluster 
called the HyApes [383]. The lower horn of Taurus 
points eastward to GEMINI, the Twins [185], with its pair 
of bright stars called CAstTor [186] and PoLLux [187]. 
The former is of the second, the latter of the first magni- 
tude. 

These two stars are very high up; but almost directly 
below them to the south is PRo’cyon [71], a fine first- 
magnitude star, belonging to the small constellation 
Canis MINor, the LitrLe Doc [70]. <A line downward 
from PRro’cyon to Sirrus and carried onward, will bring 
us quite near to the little group called CoLumMBA, the 
DovE [125]. Above this small constellation and betweer 
it and OrION, lies LEPus, the HARE [240]. From OrIon 
westward flows the faint current of ERID’/ANUS, the RIVER 


[175]; and still farther west is CETUS, the WHALE [IIo], 
part of which has already set. Northward from CETUS 
lie Pisces [320] and Aries [30], though the former is 
too near the horizon to be well seen. The distortion in 
the drawing, inevitable at the edges of any widely ex- 
tended star-map, should here be borne in mind. The 
line from Alpha (a) to Beta (B) in ARIES runs more 
directly downward in the sky than here shown. 

Just as the lines in the constellation figures far west- 
ward, or on the right, slant downward, so the lines to the 
eastward, at the left, slant upward. For example, in 
LEO, the Lion [225], the well known “‘sickle”’ leads the 
way, the star REGULUS [226] now appearing higher in 
the sky than the star Beta (B) [229]. Three or four hours 
later, however, a line connecting them will seem much 
more nearly parallel to the horizon, see p. 49. REGULUS 
has represented the Lion’s heart, his head being in the 
‘‘sickle,’’ and his tail at Beta (8). 

Just westward from LEo lie the faint stars of CANCER, 
the CRAB [50], and directly below CANCER lies the head 
of Hypra, the WATER-SNAKE [210], the most extended of 
the constellations. Hypra, like Draco at the north, is 
not at first easily distinguished, but, when its stars are 
once recognized, it becomes interesting to follow their 
clear and winding course. ALPHARD, the star in HYDRA 
marked Alpha (a) [211], is sometimes called ‘‘Cor 
Hypr#”’ or the SERPENT’S HEART. It is a fine object 
in a region large but singularly dull. CRATER, the Cup 
[140], is sometimes counted as a part of Hypra, but 
neither it nor SEXTANS, the SEXTANT [375], is brilliant 
or important. 

Between Hypra and ORION lies the dim constellation, 
Monoceros, the Unicorn [270]. Below these faint 
stars and east of CANiIs Major lie the stars of Puppis 
and Pyxis, parts of the SHrp ArGo (ArGo NaAvis) [25]. 
This is a large and brilliant constellation, but too far 
south for us to have more than a peep at it ‘‘over the 
edge of the world.” 


for Opera-Glass, fieldzGlass, and Telescope 45 


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Star Ma giitudes 
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FORNAX 


As the observer faces Southrrard) 
the stars at his lett are rising; 
those at his right are Setirrg. 


KEY-MAP TO THE SKY AS THE OBSERVER FACES SOUTH. 


MARCH 1, 8 P.M., BE Bla Oj Ser.M., 


RE Beet Omran. 


JAN. 15, 11 P.M., JAN. 1, 12 P.M. 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 42, 43. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I. FOR THE OPERA-GLASS AND FIELD-GLASS there are 
rich star-fields through CANis Major, OrRIoNn, and TAu- 
Rus. The region of the little star marked Theta (8) in 
ORION is especially beautiful, for on a clear night—par- 
ticularly if there be no moon—something may be seen 
of the great nebula [294]. 

In TAuRUS, there are fine objects in the scattered star- 
cluster called the Hyapes [383], near the bright star 
ALDEB’ARAN [381], and in the closer and more brilliant 
cluster called the PLEIADES [382]. We may also gain 
a glimpse of the cluster in GEMINI marked M 35 [188], 
that in Canis Major marked M 41 [67], and that in 
CANCER marked PRASEPE [52], the last being the most 
interesting of the three. Note also the double stars, 
Gamma (y) [242] in Lepus, and Theta (8) [386] and 
Sigma (©) [389] in TAurus. Observe also the little 
“‘neighbor”’ stars near Alpha (a) [226] and Gamma (y) 
[227] in LEo. Their connection is probably optical, see 
p. 13, rather than real. 


II. For A TWO-INCH TELESCOPE, there are, first, the 
objects already noted. The clusters, if viewed with a 
low-power eye-piece, are not only easy to find but espe- 
cially beautiful. To these may be added M 67 [55], 
just above the head of Hypra and to the right of the 
little star marked Alpha (a) in CANCER. In studying the 
great nebula in ORION, remember to view the region 
first with the lowest available power,—then use an eye- 
piece of higher power on the star Theta (8) itself [294]. 
Among the double stars of OrION, note Delta (8) [293], 
the uppermost star in the belt, and m [295], just above. 
Sigma () [299], below, appears as a fine triple. 

In Monoceros there are good objects in Beta (B) 
[271] and Epsilon (e) [272]; and, among the double stars 
of GEMINI, in Zeta (£) [193], Delta (8) [190], and Castor 
[186], though the latter are now rather high up for con- 
venient study. LrEo, however, is better placed for 
observation, and in Gamma (y) [227] we have one of the 
most beautiful of the binary systems. The two com- 


ponents are in slow motion about a common center of 
gravity. The beginner should here use a power, on a 
two-inch instrument, of about 75; nor need there be 
discouragement if the division between the stars is not 
detected in a first attempt. Tau (tr) [228], in the same 
constellation, is not so easily found, but much more 
easily divided. Far to the westward, fine and yet easy 
objects will be found in the Lambda (A) [31] and Gamma 
(y) [32] of Artes. Note also the Tau (t) [387] and the 
Eta (n) [384] of TAURUS; the double near the star marked 
To [388] in the same constellation; and—below it in 
Erip/ANus—that marked w [176]. 


III. WuitTH A THREE-INCH TELESCOPE examine, first, 
the preceding objects. Give special attention to CASTOR 
[186]; to Gamma (y) in LEo [227]; and to Theta (0) 
[294] in OrION, with the great nebula which attends it. 
All the objects mentioned for the field-glass or the two- 
inch telescope are even better subjects for the three-inch. 

In ORION use a higher power in viewing Lambda 
(A) [300] in the giant’s head, and Zeta (f) [296], the lowest 
star of the belt. Beneath Theta (8) will be found Iota 
(t) [297|—the brightest of the unmarked stars touching 
the little circle which marks the nebula. Just to the 
right, is another unmarked double—see [297] in the 
Observer’s Catalogue. RuiIGEL [292], lower to the right, 
is a difficult but noble object. 

In GeEmINI are also the double stars Kappa (k) [189], 
Epsilon (e€) [191], and Nu (v) [194]; and in CANCER, lota 
(t) [53] and Zeta (€) [54]. In Leo, the star marked 
Beta (B) [229] may be tried; as well as Alpha (a) [211] 
and Epsilon (€) [212] in HypraA; and Alpha (a) [241] in 
Lepus; but these four are difficult except in an instrument 
a little larger than three inches. In Monoceros fine 
objects will be found in the cluster to the left of Epsilon 
(€) and in that to the right of Delta (8); see [274] and 
[273]. In our present map the track of the planets lies 
through Pisces, ARIES, TAURUS, GEMINI, CANCER, and 
LEO. See p. 80. 


46 A Beginner’s Star-Book 





NIGHT-CHART TO THE SKY AS THE OBSERVER FACES NORTH, 


MAY 1, 8 P.M., APRIL 15, 9 P.M., APRIL 1, 


10 P.M., 


MARCH 15, 11 P.M., MARCH 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 48, 49. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


We may see, in turning to our diagram on p. 23, that 
the Great Dipper has now moved nearly to position C 
in its revolution round the Pole. CEPHEUS and CAssIO- 
PEIA are still, of course, on the other side of the Pole 
from the Dipper, for they have been moving round below 
the Pole while UrsA Major or the GREAT BEAR [400], 
of which the Dipper is a part, has been reaching its 
“upper culmination.” 


The stars of CEPHEUS [100] are so faint that the 
house-shaped figure is not always clearly seen when so 
near the horizon; but CAssIoPpEIA, the LADY OF THE 
CHAIR [80], while almost as low down, is gifted with 
brighter stars. As her head is supposed to be near Beta 
(B) and her feet at Epsilon (€), her position just now is 
by no means comfortable. We may see that the W 
made by her stars is even clearer in the sky than in the 
map. In the heavens, the small stars confuse the out- 
line less, and the spaces of the actual sky are greater. 
To our left from CAssIopEIA are the brilliant fields of 
PERSEUS [305]. During the early evenings of Summer, 
both constellations swing beneath the Pole and are so 
near the horizon that they are often obscured by mists; 
they are high above the Pole in the early evenings of 
Winter; see p. 58. 

Still further westward are the stars of TAuRusS, the 
BuLt [380], with the PLEIADES [382] and HYADEs [383], 
the two beautiful star-clusters of this constellation; while 
northward from Taurus and just above PERSEUS is 
AuRIGA, the CHARIOTEER [35], containing CAPELLA [36], 
one of the finest of the first-magnitude stars. We may 
note quite near CAPELLA, or the Goat, the three little 
stars called the Kids. They are Epsilon (e), Eta (), and 
Zeta ({); and their presence always establishes the 
identity of CAPELLA among the stars. AURIGA is sup- 
posed to be holding CAPELLA and her Kids in his arms. 
Above, shine the stars of GEMINI, the Twins [185], of 
which we will speak again as we face southward. 

Turning directly toward PovLaris, or the Pole-Star, 


we see that the Little Dipper of Ursa Minor, the LITTLE 
BEAR [405], is turned upward, just as the Great Dipper 
of UrsA Major is turned downward. Between the two 
and winding eastward is the long constellation called 
Draco, the DRAGON [160]. The head is formed by the 
stars Beta (B), Gamma (y), etc. Wherever we see the 
head of Draco we may know that HERCULEs [200], his 
slayer, is not far distant. The figure of the hero in the 
stars is as difficult to decipher as in the case of PERSEUS 
—and our inability to ‘‘make it out” need not discourage 
us. See the Observer’s Catalogue [200]. But to be able 
to recognize the constellation as a group of stars is im- 
portant. The light lines from Delta (8) to Nu (v) and 
95 are mere guide-lines for the telescope. Omit them in 
drawing the other lines of the constellation. First make 
clear note of the figure—somewhat like a ‘‘hopper”’ 
and sometimes called the Key-stone—made by the stars 
Pi (m), Epsilon (€), Zeta (€), and Eta (y). It is by this 
figure that the group is most easily recognized in the sky. 
Then add to your mental picture, or to your drawing, 
the line Epsilon (€), Delta (8), Alpha (a); and then the 
line Zeta (£) to Beta (B). Do not confuse Alpha (a) 
with the brighter star just below it. 


Above HERCULES shines a small but beautiful group 
called Corona, the Crown, or CoRONA BorREALIS, the 
NORTHERN CROWN [130]. Below HERCULEs rises LYRA, 
the Lyre [260], not only a fine group to the eye but of the 
deepest interest. VEGA [261], its leading star, may 
always be identified by the figure formed by the stars 
Beta (B), Gamma (y), Delta (8), Zeta (£); and by the 
further fact that just as the handle of the Little Dipper 
points in a general way toward CAPELLA, it also points, 
in its general direction, away from VEGA. It is a star 
of the first magnitude, bluish white in color, and its 
light is singularly penetrating. It is often seen long 
before the other stars appear. Much further informa- 
tion concerning this star will be found under its reference 
number [261] in the Observer’s Catalogue. 


for Opera-Glass, fFfield-Glass, and Celescope 47 


GH 


Ald Gadel pe 
* | Hyades 
. € Fi ¢ 
y fo) 


TAURUS 
r fe 2, > 


@ 
i ee % PERSEUS, : Y 2 
Pleiades Ee & - 
Pp 90! °d h 6 
OPE, 


Om CASS ( ° 
“3 


Id 
7 e| 
7 a 
TRIANGULUM ° 
Star Magnitudes 3 e 
@ist @2nd @3rd *4th*Sth and und 56 ANOROMEDA 


Cluster or Nebula 





12 


e 
CANES */ 
VENATICI 


6 2 o SERPENS 
e 
He 6 ne 3 
ce con oY 
i) 
4 


URSA MINOR 


4s the observer faces Northrard, 
the stars at his right are riS109; 
those at his left are setting. 


KEY-MAP TO THE SKY AS THE OBSERVER FACES NORTH. 
MAY 1, 8 P.M., APRIL 15, 9 P.M., APRIL 1, 10 P.M., MARCH 15, 11 P.M., MARCH 1, 12 P.M. 
FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 48, 49. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. For the Constellations See the Page Opposite. 
Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I. FOR OPERA-GLASS AND FIELD-GLASS there are rich 
fields through the Milky Way, here stretching low down 
from north to west. Note especially the regions near 
Epsilon (€) in AurrGA, near Alpha (a) in PERSEUS, and 
near Gamma (y) in CASsIOPEIA. Further still to west- 
ward there are charming views in the HyADEs [383] near 
the red star ALDEB’ARAN, and in the PLEIADES [382]. 
The names of the brighter stars in the PLEIADES are given 
in the Observer’s Catalogue. See also pp.18,19. They 
are now setting, but with the evenings of Autumn we shall 
find them again at the northeast. 

Turning, now, to the eastward or to the right, we find 
some easy double stars. Among these are the Delta (8) 
[101] of CeEpHEUS; Nu (v) [162] in the head of Draco; 
and Delta (8) [266], Zeta (£) [265], and Epsilon (e) [263] 
in Lyra. These can all be divided by a field-glass, 
steadily held. The last named star is the famous ‘‘ double- 
double,’’—for a telescope of three and one-quarter or 
three and one-half inches will show that each of its two 
components is itself a double. Above Lyra, note the 
star-cluster in HERCULES marked M 13 [206]. An opera- 
glass will barely show its existence and a field-glass will 
show it only as a very small globular patch of mist. 
A telescope of two or three or four inches will show in 
increasing measure the real nature of the object; but a 
large instrument, six to eight inches in aperture, is neces- 
sary to illustrate the basis of Herschel’s opinion that it 
contains at least 14,000 stars. An object as beautiful, 
and more within range of a good field-glass, is the double 
cluster, x-h [309], in PERSEUS. Above HERCULES let 
us note with the opera-glass the beautiful circlet of stars 
which form Corona [130]. 


II. WITH A TWO-INCH TELESCOPE, using an eye-piece 
of low power, the preceding objects are even more inter- 
esting than in the field-glass. The finest double star 
for a two-inch instrument is Zeta (t) [401] in the bend of 
the Great Dipper’s handle, but it is now inconveniently 
high. So also are the pretty doubles 12 and 15 [61, 62] 


in CANES VeENaTIcI. Well placed for observation, 
however, are such fine objects as the Beta (B) [102] and 
Xi (€) [103] in CEPHEUs; the Beta (B) in Lyra [262]; and 
the Delta (8) [202] and Alpha (a) [201] in HERCULEs. 
The last will require an eye-piece of higher power, but 
it is an object of singular charm. Note also the Tau 
(r) [387], Phi (), [391], and Eta (m), [384] of Taurus; and 
the Gamma (y) [3] of ANDROMEDA—though this beauti- 
ful object is almost too low; and try the star in AURIGA 
marked 14 [38]. Also examine the cluster M 34 [311] 
in PERSEUS. 


III. WuitH A THREE-INCH TELESCOPE, first observe 
the objects already specified for the field-glass and the 
two-inch. These are appropriate for any instrument, 
however large. Then attempt PoLaris, or the Pole- 
Star [406]. The small blue companion is now—as 
viewed in an astronomical telescope—almost directly 
above the brighter component. With an eye-piece hav- 
ing a power of from 75 to 100, the night being clear, there 
will be little difficulty in seeing it. VEGA [261], the beau- 
tiful first-magnitude star of LyrA, is an even more difficult 
double than the Pole-Star, for a telescope of three and 
one-quarter or three and one-half inches 1s usually neces- 
sary for its division. 

Other and easier doubles for a three-inch are the stars 
marked Rho (p) [204], Mu (p) [203], and 95 [205] in 
HERCULES; Zeta ({) [131] in Corona; and Iota (+) [164], 
Omicron (0), [163], and Gamma (y) [165]in Draco. The 
last may be too difficult. Try it, however, as well as 
the Eta () [264] in Lyra; the Eta (m) [308] and Zeta (f) 
[310] in PErsEus; and the fine binary star Eta () [82] 
in CASSIOPEIA. 

In addition to the clusters specified for the two-inch, 
there is the cluster between HERCULES and Draco 
marked M 92 [207]. It is almost on a line between the 
stars Pi (3) in HERCULES and Beta (B) in Draco. While 
not of such intrinsic interest as M 13 [206], it is almost 
as satisfactory an object in a three-inch instrument. 


48 H Beginner's Star=Book 





NIGHT-CHART TO THE SKY AS THE OBSERVER FACES SOUTH. 


MAY 1, 8 P.M., APRIL 15, 9 P.M., 


APRIL 1, 10 P.M., 


MARCH 15, 11 P.M., MARCH 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 46, 47- 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


As we now face southward, we find the constellation 
Leo, the Lion [225], directly before us. Lko is rather 
high at present, but the group is easily recognized from 
the figure of ‘‘the sickle,”’ formed by the stars Alpha 
(a) or REGULUS, and Eta (yn), Gamma (y), Zeta (t), Mu 
(»), and Epsilon (€). REGuLUus [226] is a first magnitude 
star, but as it lies in the track of the planets, see p. 80, 
it is sometimes outshone by the brightness of Jupiter, 
Mars, or Venus. Below LEo lies the small constella- 
tion SEXTANS, the SEXTANT [375], faint and unimportant; 
and, lower still, the stars of HyprA, the WATER-SNAKE 
[210], stretch their long course almost to the eastern 
horizon. 

The faint stars of CRATER, the Cup [140], were at one 
time regarded as part of HypRA, but they are now mapped 
separately. Corvus, the Crow—or the RAVEN,—is 
more clearly seen and is more important [135]. From 
the diagram on p. 26 we have learned to associate Cor- 
vus with the bright star Spica [416], and to note how the 
line from Gamma (y) to Delta (8) points to Spica from 
every position and at every hour. Of all the first- 
magnitude stars SpIcA is one of the whitest in color. 

VrrGo [415], to which this star belongs, has represented 
a VIRGIN or Map for untold centuries, among Chaldees, 
Egyptians, Greeks—and even among the Chinese. The 
figure is not clearly marked, the head being near Nu (v), 
the waist at Gamma (jy), the feet at Kappa (k) and Mu 
(»), the right hand at Epsilon (€), and the left arm ex- 
tended at the side, bearing a sheaf of wheat with its head 
at SpicA. To the left of Virco, and just rising, are the 
stars of Lrpra [245], the BALANCES or SCALES. 

Above V1rGo and to the left of LEo are the masses of 
little stars—extremely pretty in an opera-glass—called 
CoMA BERENICES or BERENICE’S HAIR [120]. To the 
west of LEO lie the faint stars of CANCER [50]. Next is 
the constellation GEMINI, the Twins [185], its lines 
pointing more directly downward than can be here 
indicated in the map. Castor [186] and PoLLux [187] 


make one of the finest pairs in the sky, and not far away 
to the southwest is another pair, the first-magnitude 
star Pro’cyon and the neighboring Beta (B) in the small 
constellation called Canis Minor, the LitTLE Doe [70]. 
There is no danger of confusion, however, for in the 
latter pair the difference in brightness is marked. As 
OrION [290] sets, the uprightness of the figure here 
should be corrected by the figure of the group at position 
C on p. 25. Canis Major, the GREAT DoG [65], is also 
setting, as is LEpus, the HARE [240], but all that we can 
discern of the former in latitudes as far north as New 
York, is the departing flash of the great Strius [66]. 

Still facing south, but again turning eastward—to the 
left, —we may note the constellation BOOTEs, the HERDs- 
MAN [40], distinguished for us by ArcTuRUS [41], one of 
the noblest of the first-magnitude stars. The constel- 
lation forms a kite-like figure, and we have already 
indicated the mythical outline of the Herdsman, p. 42. 
It contains nothing else so interesting, however, as its 
brightest star, of which—under its reference number—we 
have spoken in the Observer’s Catalogue. At the high 
velocity there indicated, ARCTURUS is rushing through 
space—according to Newcomb—toward the southwest, 
or in the general direction of the constellation V1RGo. 


Before leaving this map, let us note what has sometimes 
been called ‘‘the Diamond of Virgo.’”’ It is formed by 
four stars. These are Spica, ARcTURUS, the Beta (B) 
of LEo—called DENEB/oLA,—and the star in CANES 
VENATICI, the HUNTING DoGs, which bears the mark 12, 
It is often called ‘‘Cor Caroli,’’ the HEART of CHARLES 
[61], after Charles II. of England. The little constellation 
to which the last star belongs has never contained an 
outline of a Hunting Dog or of anything else, but the 
diamond-shaped figure just noted is strikingly beautiful 
and, when once recognized, is not easily forgotten. It 
may also be noted that a straight Hne across the sky is 
formed by the three bright stars SpicA, REGULUS, and 
PoLLux—almost equidistant. 


for OperazGlass, Field-Glass, and Telescope 


Pe 


e BO\OTES 


e 
*COMA*, * 
e a poEPENICES 


Mae LEO Pua to 
ey . 


< 


& 
SEAVPENS 


FS, 
ry SC QRPIUS 
e ° 


Star Magnitudes — 
@/51 @2nde3rd 4th 5th and under 
OCluster or Nebula. 





49 


45 the observer laces Soulthwara 
the starsat his lett are rising ; 
those at his rightare Setting. 


KEY-MAP TO THE SKY AS THE OBSERVER FACES SOUTH. 


MAY 1, 8 P.M., APRIL 15, 9 P.M., 


APRIL 1, 10 P.M., 


MARCH 15, 11 P.M., MARCH 1, 12 P.M, 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 46, 47- 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


Numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I. WITH OPERA-GLASS OR FIELD-GLASS examine, first, 
the region to the left, or east, of LEO covered by the 
constellation CoMA BERENICES, — ‘‘Berenice’s Hair.” 
The mythical story connected with. these little stars is 
told in the Observer’s Catalogue [120]. The scene on a 
clear night, when there is no moonlight to outshine their 
twinkling, is full of charm. 

The regions of ORION and Canis Major, at the extreme 
west, will repay us quite as well so long as these groups 
are in the sky. Here see column 1, pp. 40 and 41; but 
all the stars near this right-hand border are too near 
the horizon for satisfactory observation. The lines of 
GEMINI run much more directly downward than our map 
can indicate; as to ORION see p. 25. If we run a line, 
however, from CAsTOR to POLLUX and continue it on- 
ward we shall find just to the left of this line the pretty 
cluster, in CANCER, called PRAESEPE, or the Bee-hive 
[52]. We may also find it by searching just before the 
“sickle” of LEo. It is practically on a line, from Beta 
(B) in LEo to Eta (q), projected onward an almost equal 
distance. Among the wide double stars that may be 
divided by a field-glass, steadily held, are Gamma (y) 
[242] in LEpPus, just below Orron; Tau (7) in LEO [228]; 
and Alpha (a) [246] in LIBRA. 

Il. WITH A TWO-INCH TELESCOPE, note first such star 
clusters as that marked M 41 [67] in CANrs Major; that 
in GEMINI marked M 35 [188]; those marked merely 
with little circles in MONOCEROS near the stars 30 [275], 
and Delta (8) [273], and Epsilon (€) [274]; that marked 
M 53 [121] in ComA BERENICES. The easiest for a small 
instrument is, of course, PRAESEPE [52] in CANCER. 

Among the double stars for a two-inch telescope, three 
superb objects are now available: CAstor [186] in 
GEMINI; the star Gamma (y) [417] in Virco; and Gam- 
ma (y) [227] in the ‘‘sickle” of LEo. The last is the 
most difficult. There is a little ‘‘neighbor star,’’ only 
connected optically with the pair, that should not be 
confused with the real companion of the primary star. 


4 


The two components of the binary system are very close 
together in the field of a two-inch, and a good glass with 
a steady mounting is requisite for their division. CASTOR 
is also a superb object. Use for each of these stars 
a power of from 65 to 75. Gamma (y) in VrRGo is an 
easier object, not requiring powers quite so high and 
therefore a more beautiful pair for the beginner. 

Other double or multiple stars for the two-inch are 
Pi (a) [44] and Delta (8) [43] in BoOTES; Alpha (a) [246] in 
LisrA; Delta (8) [136] in Corvus; Tau (rt) [228] in LEO; 
Iota (+) [53] and Zeta (€) [54] in CANCER; Delta (8) 
[190] and Zeta (f) [193] in GEMINI; Beta (B) [271] and 
Epsilon (€) [272] in MONocEROS, and 14 [72] in CANIS 
Minor. The double stars further to the westward are 
noted on p. 45. They are here too near the horizon for 
satisfactory observation. 


III. WuiTH A THREE-INCH TELESCOPE, first examine 
the preceding objects. Each is not only appropriate 
for a three-inch but it may be viewed in such an instru- 
ment under far better conditions. With eye-pieces of 
the same power the field of view will be larger and it 
will be illuminated more clearly and brightly. It is 
also easier, first using an eye-piece of low power, to find 
the objects specified. Tothestar-clusters just mentioned 
add M 46 [26], almost on a line projected from Srrius 
through the Gamma (y) of Canis Major; and M 67 
[55], between CANCER and the head of Hypra. With 
eye-piece of lowest power sweep through the region of 
ViRGO just west of Epsilon (€). This is a region of many 
nebule too faint in our small instruments for individual 
classification. Add to the double-stars Alpha (a) [416], 
Theta (8) [418], and Tau (tr) [419] in Virco; Epsilon 
(€) [191], Kappa (k) [189], Nu (v) [194], and Lambda (A) 
[192] in Gemini. The last is the unmarked star form- 
ing a small triangle with Delta (8) and Zeta (€). Try, 
also, Epsilon (€) [212] in Hypra, and Beta (B) [229] in 
Leo. The track of the planets lies here through GEMINI, 
CANCER, LEO, VIRGO, and LIBRA; see p. 80. 


50 


Hl Beginner’s Star-Book 











NIGHT-CHART TO THE SKY AS THE OBSERVER FACES NORTH. 


JULY 1, 8 P.M., JUNE 15, 9 P.M., JUNE 1, 


FOR KEY-MAP TO THIS CHART 


10 P.M., MAY 15, 11 P.M., 
SEE OPPOSITE PAGE. 


MAY 1, 12 P.M. 


FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 52, 53. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


Looking northward, we now find the Great Dipper, 
part of the constellation Ursa Major [400], high up but 
slowly wheeling downward. The bowl precedes the 
handle; and as shown on p. 23, it has now passed through 
position C and is moving toward position D. The handle 
of the Dipper was supposed to represent the Bear’s 
tail; the hip being at the Dipper’s bowl, the hind feet at 
Mu (p) and at Xi (€), the forefeet at Kappa («), the ears 
at the little stars Sigma (©), etc., and the nose at Omicron 
(0). The Bear now has his head downward, his back 
being toward the Pole. The stars really form no like- 
ness to this animal or to any other. 

The line of direction to PoLaris, the Pole-Star, may 
be taken at every hour from the stars Alpha (a) and Beta 
(B) in the Great Dipper, and this line now points down- 
ward and toward the right. Poraris [406] is at the tip 
of the handle of the Little Dipper, part of the constel- 
lation UrsA Minor, or the LITTLE BEAR [405]. If we 
continue this line straight on across the sky, it will pass 
between the house-shaped figure of CEPHEUS [100], and 
the brighter group called CAssIOPEIA [80], or THE LADY 
OF THE CHAIR. ‘The line will cut through CEPHEUS not 
far from the star Gamma (¥y), and, passing on, will ‘‘find”’ 
the star Beta (B) in PEGAsus [301] when it rises above the 
horizon; see p. 54. The line will traverse an unim- 
portant group called LACERTA, the LizArpD [220]. The 
stars below this line are not high enough to be well seen, 
though the figure of the W, which represents the Chair 
of CASSIOPEIA, will doubtless be clearly marked. Above 
this line, however, lie three most interesting constella- 
tions. 


First among these, let us note CyGnus, the SWAN [145]. 
The head is supposed to be at Beta (B), the tips of the 
outstretched wings at Delta (8) and Epsilon (€), and the 
tail at Alpha (@) or DENEB [146]. These stars are more 
frequently regarded, however, as the Northern Cross; 
and when the figure is once recognized it is not easily 
forgotten. Eastward from CyGNnus, or further to the 


right, shines the small constellation called DELPHINUS, 
the DOLPHIN [155]. It presents no outline of a dolphin 
but four of its stars do form a very pretty diamond. 

Turning more directly northward, and looking higher, 
we may see—above CyGNus—the figure of Lyra, the 
LyreE [260], with its fine first-magnitude star VEGA 
[261]. Further to our left from VEGA we can detect the 
head of Draco, the DRAGON [160], with the winding 
stars of this constellation looped, as it were, in a figure 
like an arch, above the bowl of the Little Dipper. The 
head of Draco can always be found, when CYGNUS is 
in the sky, by the arms of the cross,—for a line drawn 
through them, from Epsilon (€) to Delta (8), will always 
point toward Gamma (y), Draco’s brightest star. A 
line from this star to Beta (B) at the foot of the cross 
will point directly to the little constellation SAGITTA, the 
ARROW [335], lying, as does CyGnus, full in the Milky 
Way. 


Below the Pole, too far down for good observation, lie 
the fine constellations PERSEUS [305], and AURIGA, the 
CHARIOTEER [35]. CAPELLA [36], the beautiful first- 
magnitude star of the latter group, is so brilliant that it 
may often be seen through the mists of the horizon until 
almost the very moment of its setting. With Beta (B) 
of the same constellation, it forms a pair often mistaken 
for CASTOR and PoLLux, the companion stars of GEMINI, 
the Twins [185]. These are now further to the westward. 
It should be noted, however, that the latter stars are 
nearer together—with the brighter above; not below, 
as in the case of the two bright stars of AURIGA. 

The dim stars of CANCER [50] can hardly be seen so 
near the horizon, but above them shines the ‘‘sickle”’ 
of LEo [225]. This is not turned down quite so far as 
shown here, nor is it turned up quite so far as shown 
in the next map, p. 53, but the sickle does lead the way 
downward, the other lines of the figure stretching back- 
ward and upward from it. Lynx [255], and LEo MINOR 
[235], the LitTLE Lion, are not important. 


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As the observer faces Northward, 
the stars at his right are rising; 
those at his left are setting. 


ANDROME DA 


KEY-MAP TO THE SKY AS THE OBSERVER FACES NORTH. 


JULY 1, 8 P.M., JUNE 15, 9 P.M., 


JUNE 1, 10 P.M., 


MAY 15, 11 P.M., MAY 1, 12 P.M. 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 52, 53. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer's Catalogue, p. 116. 


I. WITH OPERA-GLASS OR FIELD-GLASS follow, first, the 
course of the Milky Way as it stretches through AuRIGA, 
PERSEUS, CASSIOPEIA, and on through CEPHEUS, 
CyGnus, and SacitTa. The innumerable stars which 
compose it are massed more thickly at some points than 
at others. Near Alpha (a) in PERsEus, Gamma (y) in 
CASSIOPEIA, and along the line of the Cross in CyGNus 
—particularly from Gamma (y) to Beta (B)—there are 
tegions of especial beauty and charm. 

Note also the fine double cluster in PERsEUus, lying 
almost on a line between Eta (y) in that constellation 
and Epsilon (€) in CAssiopEIA. It is marked x-h [309]. 
Just now, however, it is too low—except in far northern 
latitudes—for satisfactory observation. Among the 
wide double stars, the following may be divided by a 
field-glass, if the glass be steadily held: the Nu (v) [162] 
in the head of Draco; Epsilon (€) [263], Delta (8) [266], 
and Zeta (f) [265] in Lyra; Delta (8) [101] in CEPHEUS; 
and Omicron (0) [148] in CyGnus. Near the foot of the 
Cross note also the little star marked 6 [426]. 

Mizar is the name of the star marked Zeta ({) [401] 
at the bend of the Dipper’s handle. Quite near, and 
involved in the same stellar system with the brighter 
star, is the small star marked g. Its name is ALCOR 
[402]. As will be seen under the reference number in 
the Observer’s Catalogue [401], recently discovered facts 
have given new interest to these well-known stars. 


II. WITH A TWO-INCH TELESCOPE the beginner should 
first examine the preceding objects. Mu1zAr, however, 
to which we have just referred, is rather high just now 
for convenient study. Toward the west—if the mists of 
the horizon have not clouded them—be sure to examine 
CASTOR [186] in GEMINI and Gamma (y) [227] in LEo. 
Both are fine objects; the latter the more difficult of the 
two. The beginner need not feel discouraged if his 
first attempt to separate the components should not 
succeed. Near to Gamma (y) is also a small ‘“‘neighbor 
star’ having only an optical connection with the binary 


system; see p. 13. The real double is a very close pair 
in either a two-inch or three-inch instrument. 

But whatever the disappointments in connection with 
the preceding star there will be none with the Beta (B) 
[147] of CyGNnus, extremely easy and yet singularly fine. 
A little closer and yet also a delightfully satisfactory 
object is the Gamma (y) [157] of DELPHINUS. Easy 
objects will also be found in the Xi (€) [103] and Beta 
(B) [102] of CEPHEUS; in the Beta (B) [262] of Lyra; in 
the Zeta (£) [54] and Iota (+) [53] of CANCER; in the 19 
of Lynx [256]; and in the Delta (8) [190] and Zeta (f) 
[193] of GEMINI—if the last named stars be not too near 
their setting to be clearly seen. 


III. WiTH A THREE-INCH TELESCOPE the objects 
already specified may be seen to even better advantage 
than with the two-inch. All should be viewed with an 
eye-piece of low power (from 40x to 60 x) except in the 
cases of the Gamma (y) [227] in LEo and CAsTor [186] 
in GEMINI. In the latter case 60 x will sometimes prove 
sufficient, though 75 x is better. Powers between 60 
and 110 will also be needed for some of the following: 
the Eta (n) [82] in CAssIoPEIA, one of the finest of binary 
systems; the Mu (p) [153] of CyGNus, just to the right, 
or east, of LACERTA; and 61 [150], Omicron (0) [148], 
and 17 [152], also in CyGNus; as well as Eta (m) [308] 
in PERsEus; and Omicron (0) [163], Iota (+) [164], and 
Gamma (y) [165] in Draco. In GEMINI, if the stars are 
not too low in the sky, try Kappa («) [189], Epsilon 
{191], and Lambda (A) [192]. The last is the unmarked 
star which forms a small triangle with Delta (8) and 
Zeta (£), both of which we have already mentioned. On 
a line extending the handle of the Little Dipper note the 
small star marked ro H [49]. 

Ir trying to divide PoLaris, the Pole-Star [406], use 
an eye-piece affording a power of from 75 to 100 on a 
three-inch instrument. At the present hour, the begin- 
ner may look for the small blue companion upward and 
toward the left from the brighter component. 


UNIVERSITY OF ILLINOW 
LIBRARY 


52 H Beginner’s Star=Book 








NIGHT-CHART TO THE SKY AS THE OBSERVER FACES SOUTH. 


JULY 1, 8 P.M., JUNE 15, 9 P.M., 


JUNE 1, 10 P.M., 


MAY 15, 11 P.M., MAY 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE. 


FOR THE SKY AS THE OBSERVER FACES NORTH, 


SEE PP. 50, 5I. 


For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. . 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


As we face toward the south, the stars of SCORPIO, or 
ScorPIus [350], lie before us—a little to the left. Scorpio 
rises at about the time ORION sets, and dominates the 
sky of midsummer almost as strikingly as ORION [290] 
dominates the sky of winter. 

We may recognize the constellation, even through the 
haze which so often lies near the horizon, by the fan-like 
figure of six bright stars. This is formed of two groups, 
of three each. Alpha (a) or ANTARES [351] with Tau (tT) 
and Sigma (©) form one group, pointing directly to the 
other—Beta (B), Delta (8), and Pi (a). These stars— 
always in the same fixed relation to each other—may 
often be seen when the rest of Scorpio is practically 
blotted out by fog or mist. The whole figure is so like 
the scorpion of the tropics, with its extended claws at 
Gamma (y) and Xi (§),—its tail at Epsilon (€) and Mu 
(w)—extending to its sting at Lambda (A), that it is 
the most realistic of the constellation outlines. 

Directly to the west, or to the right, of SCORPIO shine 
the stars of Lipra [245]—the BALANCES or SCALES. The 
fainter stars are not always visible, except when the night 
is very clear, and the group must often be recognized 
merely by Alpha (a) and Beta (8B). To the right shines 
the white light of Spica [416], the first-magnitude star 
of Virco [415]. Its recognition will be made even easier 
for us by the diagram on p. 26. 

Below Corvus, the RAVEN, or Crow [135], stretches 
the long line of Hypra [210], the WATER-SNAKE, the 
whole length of which is shown on p. 49. Below the tail 
of Hypra, very low in the sky near the center of our 
present map, are a few of the stars of CENTAURUS, the 
CENTAUR [go], one of the great constellations of the far 
southern skies. Theta (0) is the only one of its brighter 
stars that can be seen from our latitudes. 

Very high up shines Arcturus [41], the superb first- 
magnitude star of BOOTES, the HERDSMAN. To the left 
is the pretty group called CORONA, or CORONA BoREALIS, 
the NORTHERN CROWN [130]. Farther still to eastward, 


or to the left, lie HERCULES [200], and Lyra, the LYRE 
[260]; and lower down lies AguILA, the EAGLE [20], 

marked by the three stars in a row—Alpha (a) or ALTAIR 
[21], and Beta (B) and Gamma (y). These are now about 
at position A as shown in the diagram on p. 28. Through, 
the evening hours of the summer and autumn these three 
stars, which I have ventured to call ‘‘the shaft of Altair,” 
form one of the finest landmarks of the sky. In study- 
ing BodOTtes and HEeRcuLEs the reader should turn to 
what has already been said on p. 42 and p. 46. Both 
are very high at the present hour, yet their figures are 
quite distinct. Below HERcuLES and above SCORPIO 
there lies, however, one of the most difficult of the con- 
stellation outlines, OPHIUCHUS, or the SERPENT-BEARER 
[285], a difficult group. 

Inability to distinguish this constellation need cause 
the beginner no discouragement. It has baffled many a 
veteran. Note the method for learning it suggested in 
the Observer’s Catalogue [285], but if it is not clear at 
first, let it await your leisure—learning the other groups 
first. It should be studied in connection with SERPENS, 
the SERPENT [365], which lies on each side of it, the head 
to the observer’s right, the tail to the left. 


To the right of ARcTuRUS, lies the scattered cluster of 
faint stars, COMA BERENICES, or BERENICE’S Harr [120]; 
and still lower toward the west are the stars of LEO, the 
Lion [225],—but with the familiar ‘‘sickle’”’ turned 
downward more directly than here shown, with Beta 
(B) or DENEB/OLA higher up. REGULUs [226] makes with 
SpicA and ANTARES a fairly straight ine at almost 
equidistant spaces. The track of the planets, see p. 80, 
lies here through the constellations LEo, Mes LIBRA, 
Scorpius, and SaGiTtartus, the ARCHER [340]. The 
last is, as yet, hardly above the horizon, but the group 
is here outlined for observers who at a slightly later time 
may wish to trace its connection with SCORPIO; see para- 
graph 10, p. 31. Under the next map of the sky to the 
south it will receive fuller discussion; p..56. 


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AS the observer laces Soulhward, 
the Stars athis left are FUSING ¢ 
those athis right are setting. 





KEY-MAP TO THE SKY AS THE OBSERVER FACES SOUTH. 


JULY 1, 8 P.M., JUNE 15, 9 P.M., 


JUNE 1, 10 P.M., 


MAY 15, 11 P,M., MAY 1, 12 P.M. 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 50, 5I. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer's Catalogue, p. 116. 


I. WITH OPERA-GLASS OR FIELD-GLASS first note the 
interesting regions of Scorpio, following the Scorpion’s 
tail from his heart at Alpha (a) or ANTARES [351] to 
Tau (tr), and through Epsilon (€) and Nu (v), round to 
the end at Lambda (A). This is one of the rich sections 
of the Milky Way. 

The little star Mu (p) [359] in Scorpio is an easy and 
pretty double, though there is probably no real connection 
between the components; see p. 13. A field-glass will 
also indicate the delicate glimmer of the clusters marked 
M 80 [355], M 6 [356], and M 7 [357], provided the night 
be clear and the horizon unburdened by mist or fog. The 
same may be said of the clusters in SAGITTARIUS, the 
ARCHER [340], as soon as the fields of this constellation 
rise—a little later—into better position for observation. 
The easiest of these are M 8 [341] and M 24 [345]. 

Among the double stars that may be divided by a 
field-glass, steadily held, are the Alpha («) [246] of Lipra, 
the Tau (r) [228] of LEo, and the Nu (v) [353] of Scorpio. 
The last is the small star, unmarked, just to the left, or 
east, of Beta (B). With opera-glass or field-glass do 
not fail to sweep through the fine scattered cluster called 
CoMA BERENICES, or BERENICE’S Harr [120], lying just 
above a line connecting ArcTuRUS and the Beta (B) of 
Leo. ‘Trace out, also, the pretty figure of Corona, the 
Crown [130]. There is a cluster of 8th magnitude stars 
near to Beta (B) in OpHrucHus [288]. 


II. WITH A TWO-INCH TELESCOPE, examine, first, the 
objects already noted; especially the Alpha (a) [246] of 
LiprA, and the double stars of Scorrro, Beta (B) [352], 
Nu (v) [353], and Mu (p) [359]. These are all extremely 
easy and yet none the less interesting. In the case of 
Nu (v) [353], it is worth while to remember that each 
of the two components is itself a double star when viewed 
in a very large telescope. In addition to the above try 
Sigma (v) [358]; and Xi (€) [354], above Beta (B) in the 
same constellation; Delta (8) [136] in Corvus; the Gam- 
ma (y) [417] in VirGo; and the Gamma (y) [227] in LEo. 


For the last, see also the text under the northward map 
for this same hour; p. 51. 

Turning eastward, or to the left, try the stars marked 
67 [286] and 7o [287] in OpHtucHUS—the former is the 
easier; and Theta (®) [368] in SERPENS. The last named 
star is not easily found when so low in the sky, but we 
may note that it lies to our left from OpHIuCcHUS, just 
to one side of a line connecting the Zeta (€) and Lambda 
(A) of AgumLA. You will see from the Night-Chart 
that each of these guide stars is one of an obvious pair, 
Another method for finding our object is noted in the 
Observer’s Catalogue. Space has been given to such 
directions because the Theta (8) [368] of SERPENS is of 
unusual charm and beauty. 


III. WuiTH A THREE-INCH TELESCOPE and with instru- 
ments larger than a three-inch the objects already named 
should first have careful examination. To these*may 
be added the Alpha (a) [416], Theta (®) [418], and Tau 
(r) [419] of VirGO; the Iota (t) [248] of Lipra; the Xi 
(€) [251] of Lupus, just below Scorpio; the Alph’ (a) 
[201] of HERCULES, a superb object; and—in the Same 
constellation—the stars marked Mu (p) [203], 95 [205], 
Gamma (y) [208], and Rho (p) [204]. Try also the Zeta 
(€) [131] of Corona; and the Mu (p) [47], Delta (8) [43], 
Xi (€) [43 b], Pi () [44], and Epsilon (€) [42] of Bo6TEs. 
The last named star is a fine object but difficult except in 
a larger telescope. A number of the stars just mentioned 
are so easy as to be properly objects for a two-inch, but 
they are now so high that an instrument of larger aper- 
ture, with a low-power eye-piece, will find them more 
readily and permit a more satisfactory view of them. 
View also with such an eye-piece the clusters and nebulze 
M 17 [344], M 20 [342], and M 22 [343] in SAGITTARIUS, as 
well as those already mentioned. The cluster M 5 [371] 
in SERPENS forms an equilateral triangle with Mu (p) and 
Epsilon (€) in that constellation; or it may be found by 
a line from Iota (t) to Beta (B) in Lipra continued 
onward a like distance. 





54 H Beginner's Star=Book 





NIGHT-CHART TO THE’ SKY AS THE OBSERVER FACES NORTH. 


SEPT yo nave, AUG. 15, 9 P.M., 


AUG. 1, 10 P.M., 


JULY 15, 11 P.M., JULY 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 56, 57- 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


As we face toward the north, we find that the Great ~ 


Dipper, in its revolution round the Pole, is at our left, 
rather low, with the bowl of the Dipper turned eastward. 
If we turn to the diagram on p. 23, we may see that the 
Dipper is proceeding now from position D to position A, 
its stars Beta (B) and Alpha (a) still pointing, however, 
to PoLaris, the Pole-Star [406]. 

Ursa Major, or the GREAT BEAR [400], of which the 
Great Dipper is the only conspicuous part, is supposed 
to have his nose at Omicron (0), his ears at Sigma () 
and Rho (p), his forefeet at Kappa («) and Iota (+), and 
his hind feet at Mu () and at Xi (€). There is a long 
tail—quite contrary to what we know of bears—and this 
tail is the ‘handle’? of our Dipper,—the stars from 
Delta (8) to Eta (m). The Pole-Star is, of course, the 
brightest object in UrsA Minor, the LITTLE BEAR [405], 
the chief stars of which make the outline of what we call 
the Little Dipper. 

A dotted line in the Key Map will be seen to run from 
the ‘‘Pointers’’ Alpha (a) and Beta (B) in the Great 
Dipper to Portaris. If we continue this line clear across 
the northern sky, it will pass through the roof of the dim 
house-shaped figure called CEPHEUsS [100], dividing it 
from the W-shaped figure of CASSIOPEIA [80], just below, 
and will at length ‘“‘find” the star Beta (B) in the great 
square of PEGAsus, the WINGED Horse [301]. This 
square is formed by four bright stars, the Beta (B), 
Alpha (a), and Gamma (y) of PEGAsus, and the Alpha (a) 
of ANDROMEDA [1]. Here, however, let us note that so 
large a figure, coming at the very edge of the map, suffers 
an unusual amount of distortion; see pp. 4 and 6. Keep 
in mind, therefore, the fact that the upward lines which 
form in the Key Map the longer sides of the square, bear 
toward the right rather than toward the left, and are thus 
at present more nearly parallel to the horizon than they 
appear to beinthe map. Not that they are now so level 
with the horizon as drawnonp.57. Thetruth of the case 
—which could not be well shown except on a globe—lies 


between the two representations; and the observer, by one 
glance at the actual sky, will be able to make the needed 
correction. We will speak of the figure of PEGAsuS 
under our southward map, p. 56, where also the Northern 
Cross, in CyGNus, the SWAN [145] is fully drawn. 


From Prcasus the fine constellation of ANDROMEDA, 
the story of which will be found in ‘the Observer’s Cata- 
logue [1], stretches away,:in an almost straight line, 
toward PERSEUS [305], thé Alpha (a) of PERSEUS seeming 
to terminate a fine series of almost equi-distant second- 
magnitude stars,—the others being the Beta (B) of PEGa- 
sus, and the Alpha (a), Beta (B), and Gamma (y) of 
ANDROMEDA. PERSEUS, moving to the rescue, bears 
an uplifted sword—the handle being at the cluster 
marked x-h [309]—and carries also the terrible head of 
Medusa, represented by Beta (B) or Algol [307]. To 
the right of PERSEUS and eastward from ANDROMEDA, the 
stars of TRIANGULUM, the TRIANGLE [395], ARIES, the 
Ram [30], and Piscrs, the FisHEs [320], are just rising, 
but the last named is too low down as yet for clear 
observation. 

Looking again directly north, we see that the tail of 
Draco, the DRAGON [160], trails downward between the 
Great Dipper and the Little Dipper, the Dragon’s head 
being high above us at the stars Gamma (y) and Beta 
(B). The handle of the Great Dipper, if we continue 
its curve, points us to the great star ArcTuRUusS [41] in 
BoétEs, the HERDSMAN [40]. The kite-shaped figure 
points more directly downward, however, than shown 
above,—ARCTURUs being much lower in the west than 
Beta (B). Just to the left from the Dipper is the small 
constellation called CANES VENATICI, the HuntinG Docs 
[60]. They are supposed to belong to the HERDSMAN 
and to be aiding him as he chases the GREAT BEAR round 
the Pole. They form, of course, no outline of dogs or of 
anything else. Still further to our left, or westward, 
lies the scattered cluster of little stars called Coma 
BERENICES, or BERENICE’S HAIR [120]. 


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KEY-MAP TO THE SKY AS THE OBSERVER FACES NORTH. 


SEPT. 1,8 P.M., AUG. 15, 9 P.M., AUG. 


1, 


10 P.M., JULY 15, 11 P.M.,, JULY 1, 12 P.M, 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 56, 57. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer's Catalogue, p. 116. 


I. WITH OPERA-GLASS AND FIELD-GLASS, first observe 
the varied cluster of small stars called CoMA BERENICES, 
or BERENICE’S Hair [120]. It may be found by prolong- 
ing an imaginary line from PoLaris to Epsilon (€) in the 
handle of the Great Dipper. 

At the bend in the Dipper’s handle note the little star 
marked g. It is called ALCor [402], and the bright star 
quite near it is called Mizar [401]. Note also the group 
of little stars just above, at Theta (8). These belong to 
Bodtes. There is another little group marking the 
Bear’s ear at Sigma (7) in UrsA Major. The Milky 
Way is now almost perpendicular to the horizon, run- 
ning through PERSEUS, CASSIOPEIA, and the corner of 
CEPHEUS, to CyGNus. See p. 19. 

In PERSEUS there is a star-field of exceptional beauty 
near the star Alpha (a) [306]. There are other fine fields 
in CASSIOPEIA; and the famous double cluster which 
marks the sword handle of PERsSEUus lies between these 
two constellations, almost on a line between Delta (8) 
in the former group and Eta (m) in the latter. It is 
marked x-h [309]. 

Among the double stars that may be divided by a 
field-glass or opera-glass, held steadily, are Nu (v) [162] 
in the head of Draco; the star marked 15 [62] in CANES 
VENATICI; Delta (8) [101] in CEPHEUs; and the little star 
marked 56 [5] in ANDROMEDA. The last is in line with 
the Gamma (y) and Beta (B) of TRIANGULUM. 


II. WITH A TWO-INCH TELESCOPE, first examine the 
objects already mentioned, noting especially the star 
marked Zeta (€) [401], at the bend in the Dipper’s handle, 
for—as will be seen from the Observer’s Catalogue—it 
is an object of especial interest and importance. 

In the group called CANES VENATICI, note not only 
15, to which we have already referred, but the star 
marked 12 [61]; and, almost on a line with these stars, 
the place of the nebula marked M 51 [63]. This is 
beyond the scope of small instruments. It is here indi- 
cated merely because its singular structure—see p. II— 


has made its location a matter of general interest. The 
star 12 [61] is a beautiful and easy double; it is in line 
with PoLaris and the star Epsilon (€) in the handle of 
the Great Dipper. A glimpse may now be had of the 
great nebula in ANDROMEDA, M 31 [2], forming a triangle 
with the little stars Nu (v) and 32. Note also the cluster 
M 34 [311] in PERsEus, M 33 [396], above the Alpha (a) 
of TRIANGULUM, and M 3 [64], almost on a line between 
ARCTURUS and the star 72 of CANES VENATICI. Other 
double stars for a two-inch instrument are Mu (p) [47], 
Delta (8) [43], and Pi (1) [44] in BoGTEs; and Kappa (k) 
[45] and Iota (+) [46] in the same constellation. The 
two just mentioned are almost in UrsA Major, being 
above, and to the right of, the tip of the Dipper’s handle. 
Examine also the Xi (€) [103] and Beta (B) [102] of CE- 
PHEUS; the Lambda (A) [31] and Gamma (y) [32] of 
Artiges; and the Gamma (y) [3] of ANDROMEDA. The 
last is one of the most charming of all the double stars. 


III. WuTH A THREE-INCH TELESCOPE, the preceding 
objects may be seen to still better advantage: all should 
be examined, for they are not any less appropriate for a 
three-inch. In addition to these, try the double stars Eta 
(n) [308] and Zeta (£) [310] in PERsEUus; and Iota (+) [83] 
and Eta (y) [82] in CAssIOpEIA,—the latter a beautiful 
and interesting binary system. 

An imaginary line prolonging the handle of the Little 
Dipper will find the little star marked 19 H [49], an easy 
double. Use a low power eye-piece. Upon the other 
hand, the star Epsilon (€) [42] in BoOtTEs will demand 
an eye-piece of high power, and the beginner may need a 
telescope of larger size, three and one-quarter to three 
and three-quarter inches of aperture, for its division. 
The contrast in the colors of the components is very fine. 
Poraris, the Pole-Star [406], can be divided by a three- 
inch instrument, with an eye-piece having a power of 
75 to 100. The small blue companion is always worth 
seeing and pondering. At this hour it is to the left, 
but downward, from the brighter component. 


56 - Hh Beginner’s Star-Book 





NIGHT-CHART TO THE SKY AS THE OBSERVER FACES SOUTH. 


SEPT. 1, 8 P.M., AUG. 15, 9 P.M., 


AUG. 1, 10 P.M., 


JULY 15, 11 P.M., JULY 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 54, 55: 
For the sky at other Dates and Hours see Time Schedule,’p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


Facing south, we now find the stars of SAGITTARIUS, 
the ARCHER [340], directly before us, low toward the 
horizon. The ARCHER was supposed to be a Centaur, 
but nothing of this creature—half-horse and half-man— 
appears in the outline of the stars. 

The bow, however, is clearly pictured by the stars 
Lambda (A), Delta (68) and Epsilon (€). The arrow’s 
tip is at Gamma (y) and the hand is at Zeta (€), drawing 
back the arrow for its flight toward Scorpius. The 
head of the ARCHER is at Pi (w). The stars Lambda (A), 
Phi (@), Sigma (~), Tau (7), and Zeta (€) form, if taken 
by themselves, a figure like a dipper up-side-down; and 
this has long been recognized as the ‘‘ Milk Dipper.” 

Eastward or to the left, shines ALTAIR [21], the beauti- 
ful first-magnitude star of AQuILA, the EAGLE [20]. It 
can always be identified on a clear night by the two 
almost equidistant stars Gamma (y) and Beta (B). They 
serve also to point us, in a general way, toward Lyra, 
the Lyre [260], with its bright star VEGA [261]; and— 
in the other direction—toward the faint stars of CAPRI- 
CORNUS, the SEA GoaT [75]. See also p. 28. 

To the east of Lyra shines CyGnus, the Swan [145], 
forming also the Northern Cross; and to westward from 
Lyra is the figure of HERCULEs [200], but these constel- 
lations are now so inconveniently placed for observation 
that we only refer, here, to pp. 38 and 46, and to what is 
said concerning them under their reference numbers in 
the Observer’s Catalogue. To the latter source we may 
also refer for the figure of OpHiucHus, the SERPENT- 
BEARER [285], and SERPENS, the SERPENT [365], both of 
Bae" are below HERCULES and somewhat lower in the 
sky. 

Returning to AQUILA, we may note that the stars of the 
constellation really form no likeness of an eagle, and we 
are able to draw the outline shown in the Key-Map, 
only by making a somewhat arbitrary selection of the 
stars. The same may be said of AQUARIUS, the WATER- 
BEARER [15], except that here the effort to find an image 


appropriate to the name must be even more futile. We 
must assume that the man lies almost on his back, with 
shoulders at Alpha (@) and Beta (B), waist at Delta (8) 
and knees at Lambda (A) and Phi ($). One object, at 
least, is clearly and prettily marked,—the mouth of the 
Water Jar, formed by the little Y-shaped figure at 
Pi (1), Eta (yn), and Gamma (y). In the lines of faint 
stars running downward through Phi (¢) and Omega (@), 
and onward, some have seen the trickling of a jewelled 
stream into the mouth of the SOUTHERN FisH, Piscis 
AUSTRINUS [330];—for the mouth of the Fish i§ marked 
by FoMALHAUT [331], a fine first-magnitude star. At 
this hour, precisely, FOMALHAUT is not yet quite above 
the horizon in our northern latitudes. 

Northward from AQUARIUS, the great square of PEGA- 
sus, the WINGED Horse [301], is now apparent. As 
PEGASUS is so great in size and as it is divided between 
the south and north, the text and maps here should be 
supplemented by those on pp. 54, 55. The shoulders 
and body of the horse are represented by the ‘“‘square’’; 
the head is toward the south, at the stars Zeta (f), 
Theta (8), and Epsilon (€); and the forefeet are at Eta 
(n) and Kappa («). The huge animal has, therefore, 
his back toward the horizon, his feet in air. The “‘square”’ 
is formed only by including the Alpha (a) of ANDROMEDA, 
as explained under the preceding Night Chart; and the 
explanation of the distortion there, is applicable here. 

Turning again to the south, we see that the stars of 
SCORPIUS, or ScoRPIO [350], are sinking toward the west, 
but the fan-shaped figure made by the six bright stars— 
ANTARES [351], Tau (tT) and Sigma (©) in one group; and 
Beta (B) Delta (8), Pi (wr) in the other—is still distinct. 
Westward from Scorpio is Lipra [245], the BALANCES 
or SCALEs; and still farther westward and northward, 
the superb ArcTuRUS [41] leads the HERDSMAN, BOOTEs, 
beyond our ken. Between the latter constellation and 
HERCULES [200] shines the charming figure of CORONA 
BorREALIS [130], or the NORTHERN CROWN, 


for Opera-Glass, Field-Glass, and Telescope 


37 






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Ost @2ndesrde4ihe5ih and unde) y CA F en e vy the stars at hislett are rising ; 

OGluster or Nebula. SS a” # hose athis right are serting, 


KEY-MAP TO THE SKY AS THE OBSERVER FACES SOUTH, 

AUG. 15, 9 P.M., AUG. 1, 10 P.M., JULY 15, 11 P.M., 
FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 

FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 54, 55. 


SEPT. 1, S& P.M., JULY 1, 12 P.M. 


For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I. WITH OPERA-GLASS AND FIELD-GLASS sweep, first, 
through the course of the Milky Way. It here runs 
almost through the centre of the map,—from CyGnus, 
through SAGiTTA, AQUILA, and SAGITTARIUS,—swerving 
slightly westward as it descends, and including the tail 
of Scorpio. 

In this region we shall be able on a clear, moonless 
night to catch a glimpse of the clusters marked M 8 
[341], M 7 [357], M 6 [356], and M 22 [343]; and possibly 
of 80 [355] also—just on a line, in SCoRPIO, between 
Alpha (a) and Beta (8). Among larger groups the stars 
of Corona [130] form a beautiful spectacle. A field- 
glass or, in some cases, an opera-glass will divide the 
following double stars: those marked Alpha (a) [76] and 
Beta (B) [77] in Capricornus; the star marked 6 [426] 
near the foot of the Cross in Cyenus; Epsilon (e€) [263], 
Delta (8) [266], and Zeta (£) [265] in Lyra,—now very 
high up; Mu (j) [359] in Scorpio, and Alpha (a) [246] in 
LIBRA, now low in the southwest. 


II. For A TWO-INCH TELESCOPE, the preceding 
objects are of course available; and all are worthy of the 
beginner’s interest and study. Try also the double 
stars marked Sigma (©) [358], Beta (B) [352], and Nu (v) 
[353] in Scorpio,—the last is the Senin star to 
the left from Beta (B). Examine Xi (€) [354] also, just 
above Beta (8B). These will be found easy but very fine. 
Try, too, the stars 67 [286] and 7o |287] 1n OPHIUCHUs; 
and Theta (8) [368] in SERPENS. The latter is the easiest 
of the three, and one of the loveliest of its class. 

We have already spoken frequently of the star in 
CyGnus, marked 61 [150]; and of Beta (B) [147],—one of 
the finest objects for a small instrument. Try also the 
doubles in Lyra, marked Beta (8) [262] and Eta (m) 
[264]. Interesting double stars are also to be found in 
the Alpha (a) [201] and Delta (8) [202] of HERCULEsS— 
the former is especially beautiful; in the Zeta (€) [131] 
of Corona; and in the Pi (a) [44] and Delta (8) [43] of 
the constellation BoOTEs. 


Returning to the region of AguILA, the Gamma (y) 
[157] of DELPHINUS, not far from ALTArIR, should not be 
forgotten. Another fine double, though a little more 
difficult than the last, is the Zeta (€) [17] of AQUARIUS, 
the star at the centre of the little Y-shaped figure that 
marks the mouth of the water-jar. Try also the star 
Psi (b’) [18] in the same constellation. As Piscts AUSTRI- 

NUS, the SOUTHERN FIsH, rises a little higher in its course, 
the star Beta (B) [332] ] will be found an easy double. 


III. WiTH A THREE-INCH TELESCOPE, the beginner 
will do well to examine the objects already mentioned for 
the field-glass and the two-inch. With an eye-piece of 
low power, we may note the following star clusters and 
nebulae—if the air be clear and the sky be free from 
moonlight. To those already listed, add M 22 [343] and 
M 17 [344] in Sacitrarius; M 12 [289] in OpHiucHus; 
M 13 [206] in HERCULEs, though this is now too high for 
convenient examination; M 2 [16] in Aquarius; M 11 
[23] in AguiILa, near to Lambda (A); M 27 [427] in VuL- 
PECULA, forming an acute triangle with the Eta (nm) 
and Gamma (y) of SacttTa; M 15 [303], in line with the 
Theta (8) and Epsilon (€) of PEGAsus; and—far westward 
—M 5 [371] in SERPENS, called a “variable’’ cluster 
because in it have been detected more than a hundred 
variable stars. There is also a pretty cluster near Beta 
(B) in OPHIUCHUS, see [288]. 

To the double stars already listed, add the Gamma 
(y) [333] of Prscrs AusTRINUuS; the Pi (7) [79] of CAprI- 
cornus; the Epsilon (€) [302] of PEGAsus; the Alpha 
(a) [156] of DELPHINUS; 77 [152] in CyGNus; Mu (p) 
[203], 95 [205], and Rho (p) [204] and Gamma (y) [208] 
in HercuLes; Jota (+) [248] in Lipra; and Epsilon (e) 
[42] in Bodétes. The last may require a telescope of 
slightly larger aperture. Such may also prove necessary 
with VEGA in LyrA [261] and ANTARES [351] in SCORPIO. 
The track of the planets, see p. 80, passes here through 
Virco, LisprA, SCORPIUS, SAGITTARIUS, CAPRICORNUS, 
AQUARIUS, and PISCEs. 


58 A Beginner’s StaraBook 





NIGHT-CHART TO THE SKY AS THE OBSERVER FACES NORTH. 


OCT.-15, 9 P.M., 


OCT. 1, 10 P.M., 


SEPT. 15, 11 P.M., SEPT. 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 60, 61. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


The Great Dipper is now directly before us, low in the 
sky, as we face due north. From the diagram on p. 23, 
we may see that, in its revolution round the Pole of the 
heavens, it has passed from position A to position B; 
from B to C; from C to D; and is now almost at position 
A again. These seven stars are but the brighter part 
of the constellation UrsA Major, the GREAT BEAR 
[400]. 

Two of these stars, Alpha (a) and Beta (8), point us 
always in the general direction of POLARIS, the Pole-star, 
which is the brightest star in the Little Dipper. Its 
outline is not always clear because some of its stars are 
quite faint, but it forms the chief part of UrsA MINor, 
the LITTLE BEAR [405]. 

Looking carefully at the Little Dipper, we may see that 
its handle, with PoLaRis at the tip, is pointing toward the 
east at our right hand. In a general way it points us 
toward two bright stars,—stars of the first magnitude. 
The whiter of these stars is CAPELLA [36], the finest 
object in the constellation AuRIGA, the CHARIOTEER 
[35]. The reddish star is ALDEB’ARAN [381] in the con- 
stellation TAURUS, the BULL [380]. Of the constellations 
called Lynx [255] and CAMELOPARDUS the GIRAFFE [48], 
little need be said, as they are too faint and unimportant 
for discussion here. 

We shall see near CAPELLA (the name means literally 
She-Goat) three little stars forming an acute triangle. 
These, Epsilon (€), Zeta (€), and Eta (n), have for un- 
counted centuries been known as ‘‘The Kids.”” AuRIGA, 
the CHARIOTEER, is supposed to be bearing the Goat and 
her kids in his arms. TAuRUsS, the BULL, with his red 
eye at ALDEB’ARAN, and his two horns stretching away to 
Zeta (£) and Beta (B), shares the latter star with AURIGA; 
though, strictly, it belongs to TAurus. In this great 
constellation lie the two fine star-clusters, the PLEIADES 
[382] and the Hyapes [383]. The PLEIADES represent 
perhaps the most widely interesting of all the minor 
star groups: see pp. 17, 19. In looking at the HyApEs, 


we should remember that the apex of the triangular figure 
ending at Gamma (y) is not tipped upward so much as 
in the diagram. We may here correct the distortion at 
the map’s edge by noting that the line, for example, 
from Alpha (a) to Gamma (y) is more nearly parallel 
to the horizon. 

Above AuRIGA shines PERSEUS [305], and to the left 
we may see the W-shaped figure of CAssIopEIA [80], 
sometimes called the LADY OF THE CHAIR; and the house- 
shaped figure of CEpHEUS [100]. Of these groups we 
have spoken more fully on pp. 46 and 50. We may find 
the head of Draco, the DRAGON [160], by noting that it 
is practically in line with Beta (B) in Ursa Minor, and 
the bright star VEGAin Lyra. Gamma (y), the brightest 
of Draco’s stars, is also in line with the cross-beam of 
the Northern Cross in CyGNus [145]. 


Lyra, or the Lyre [260], is a small constellation, but 
one of the most interesting. It may be identified by 
the brilliancy of VEGA [261], its beautiful first-magni- 
tude star, and by the figure formed by the smaller stars, 
Beta (B), Delta (8), Gamma (y), and Zeta (£). Below 
Lyra are the stars of HERCULES [200]. Here the begin- 
ner should first trace the outline of the ‘‘hopper” or the 
‘‘key-stone”’ formed by Pi (1), Epsilon (€), Zeta (€), and 
Eta (yn). To these should be added the line from Epsilon 
(€) to Delta (8) and Alpha (a), and the line Beta (B) to 
Zeta (€). The lines to Mu (p) and 95 are merely to aid 
the user of a telescope, and are not important. Below 
HERCULES is the pretty figure of CORONA, or CORONA 
BorEALIs, the NORTHERN CROWN [130]. Very low at 
the northwest, the few remaining stars of BoOTEs, the 
HERDSMAN [40], are setting, and at the northeast, at our 
right, the stars of GEMINI, the Twins [185], are just 
rising; see the maps on pp. 38 and 40, as these come next, 
in the order of our series. CASTOR [186] rises first, soon 
to be followed by the more brilliant PoLLux [187]. The 
whole constellation is of especial importance; see Ob- 
server’s Catalogue, under reference numbers just given. 


for Opera-Glass, field-Glass, and Telescope 59 


A 2° 
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O51 @2nd@ 5rd 84th Sth ond unde! the stars at Ais ri ghlare r1Sing; 
OCluster or Nebula e@ those at his left are setting. 





KEY-MAP TO THE SKY AS THE OBSERVER FACES NORTH. 
NOV. 1, 8 P.M., OcT. 15, 9 P.M., OCT. 1, 10 P.M., SEPT. 15, 11 P.M., SEPT. 1, 12 P.M. 
FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES SOUTH, SEE PP. 60, OI. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. For the Constellations See the Page Opposite. 
The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I. FOR OPERA-GLASS OR FIELD-GLASS, there are now () [47], Kappa («) [45], and Iota (+) [46] in BodéTEs. 
before us some interesting regions of the Milky Way, ‘The last two are now just above Eta (yn) of Ursa Major, 
which runs, here, through CyGNnus, CEpHEUS—near at the end of the Dipper’s handle. At the bend of the 
Delta (5); Cassiopeia; PERSEUS—note especially the handle is Zeta (£) [401], or Mizar, probably the most 
field about Alpha (a) [306]; and AuricA—flowing by interesting and important of all the double stars within 
Epsilon (€) and to the right of Theta (0); and on through range of a two-inch telescope. The star marked Beta 
the feet of Gemini. Note here the fine cluster marked  (f) [147] at the foot of the Cross in CyGNUs is now very 
M 35 [188], forming an obtuse triangle with the stars high up, but it is a beautiful object, and well worth the 
Mu (p) and Eta (n). effort if the beginner can get it into the field of his in- 

The most beautiful and impressive of all spectacles strument. Even finer is the Gamma (y) [3] of ANDROM- 
for such a glass is, of course, the PLEIADES [382]. Note EDA,—which forms a right angled triangle with the 
also the HyapEs [383]. In this group itis well to observe Alpha (@) and Beta (B) of PERSEUs. 
especially the little pairs marked Theta (0) [386] and III. WuITH A THREE-INCH TELESCOPE the preceding 
Sigma (¢) [389]. There is a slight distortion in the map objects are available. The Alpha (@) [201] of HERCULES; 
here which can be easily corrected by the suggestions the Beta (B) [1 47] of CyGnus; the Gamma (y) [3] of 
given in col. 2, p. 58. ANDROMEDA; and the Zeta (£) [401] of Ursa Major are 

Turning westward, or to the left, we may detect, per- of especial interest and beauty. The star-clusters, in- 
haps, the double cluster marked x-h [309] between cluding the PLEIADES [382] and the Hyapes [383] in 
PERSEus and CAssIOPpEIA. On p. 4, and under its refer- Taurus, and M 35 [188] in Gemini are fine under low 
ence number in the Observer’s Catalogue, we have powers. 
spoken of it more fully. To the double stars listed for the field-glass and the 

Among the important double stars, Zeta (£) [401] two-inch telescope, the following may be added to the list 
and g at the bend in the handle of the Great Dipper may for a three-inch: The Zeta (£) [131] of Corona; the 
usually be divided from each other by the unaided eye. stars marked 95 [205], Mu () [203], Rho (p) [204], and 
These are named Mizar and ALcoR; see p. 39. Zeta Gamma (y) [208] of HERCULES; the Beta (B) [262] and 
(f) itself will of course require a telescope for its division. Eta (yn) [264] of Lyra; the star marked 17 [152] in 
The preceding stars and some of the following may be (Cygnus; Delta (8) [166], Omicron (0) [163], Iota (\) 
divided by an opera-glass, as well as by a field-glass:— [164], and Gamma (y) [165] in Draco; the star marked 
the Nu (v) [162] in the head of Draco; Epsilon (€) [263], 19 H [49] to the right of Potaris; Eta (9) [308] and— 
Delta (5) [266], and Zeta (€) [265] in Lyra; Delta (8) more difficult—Zeta (£) [310] in PERSEUS; and Iota (t) 
[101] in CepHEus; and Omicron (0) [148] in CyGNnus. [83] and Eta (m) [82] in CASSIOPEIA. The last two stars 

II. WITH A TWO-INCH TELESCOPE, the objects al- are not easy objects, but the latter represents an inter- 
ready listed may be examined to even greater advantage. esting binary system, and the contrast in the colors of 
Each is worth while. To the double stars may be added the components is singularly fine. _PoLaris [406], or the 
the Tau (r) [387], Phi (@) [391], and Eta () [384] of | Pole-Star, is always of interest; and the ninth-magnitude 
Taurus; the star marked 74 in AurRIGA [38]; Beta (B) companion will be found at this hour almost directly 
[102] and Xi (€) [103] in CEPHEUsS; Delta (8) [202] and below the brighter component. Try a power of 75; an 
Alpha (a) [201] in HERCULES; and Delta (8) [43], Mu even lower power is often sufficient. 


50 H Beginner's Star-Book 











NIGHT-CHART TO THE SKY AS THE OBSERVER FACES SOUTH. 


NOV. 1, 8 P.M., OCT. 15, 9 P.M., 


ocT. 1, 10 P.M., 


SEPT. 15, 11 P.M., SEPT. 1, 12 P.M. 


FOR KEY-MAP TO THIS CHART SEE OPPOSITE PAGE. 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 58, 59. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Constellations. 


For the Telescopic Objects See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


At this hour, as we face southward, the bright first- 
magnitude star directly before us, low in the sky, is 
called FOMALHAUT [331]. This is the brightest object 
in the SOUTHERN FisuH, or Piscis AUSTRINUS [330] as 
the constellation is called in Latin. Above it is AQua- 
RIUS [15], the WATER-BEARER, looking even less like the 
figure of a man than the stars below look like a fish. 

The mouth of the water-jar in AQUARIUS is marked by 
the little Y-shaped figure at Pi (a), Eta (n), and Gamma 
(y). This is the group by which the constellation is 
usually identified. AQUARIUS is represented with head 
near the nebula marked M 2; shoulders at Alpha (a) 
and Beta (8); waist at Delta (8), knees at Lambda (A) 
and Phi ($), and feet about at Omega (w). The present 
position of the body is thus almost parallel to the horizon, 


Above AQUARIUS is PEGASUS, the WINGED Horse [301], 
the head represented by the obtuse triangle, Zeta (f), 
Theta (8), Epsilon (€); and the forefeet by the stars 
Beta (B), Eta (ny), Pi (4); and Lambda (A) to Kappa (k). 
The shoulders and body are represented by the ‘“‘great 
square,’’ the stars Alpha (4), Gamma (y), and Beta (B) 
of PEGAsus and the Alpha (a) of ANDROMEDA. As is 
the case with many of the constellations, the figure is 
not complete. 

From the square of PEGAsus, ANDROMEDA [I] stretches 
in an almost straight line; see p. 54. Lower down are 
TRIANGULUM, the TRIANGLE [395]; ARIES, the RAM [30]; 
and Pisces, the FisHEs [320]—not to be confused with 
Piscis AUSTRINUS of which we have already spoken. The 
stars of Pisces are faint, but an imaginary line from Alpha 
(a) to Beta (B) in Arigs, if continued onward, will cross 
the two lines of stars which meet at a point and form the 
eastern end of the constellation. Farther toward the 
west, or to the right, the other termination of the group 
is formed by the pretty chaplet of stars at Theta (6), 
Lambda (A), Gamma (y), etc. Many of these stars are 
too faint, except on very clear nights, to be seen without 
an opera-glass. Alpha (a) is the brightest object of the 


constellation. In some of the ancient atlases the stars 
from Alpha (a) to Eta (n), etc., marked the ‘‘Eastern”’ 
Fish, those at the chaplet the ‘‘ Western’’ Fish, and the 
stars from Mu (p) to Omega () represented a ribbon or 
garland binding them together. 

Near the Alpha (a) of PrscEs lies the head of the huge 
constellation called Crtus, the WHALE [110]. The 
creature’s head is formed by the stars Alpha (a), Lambda 
(A), Mu (p), Gamma (y), etc., and his great tail stretches 
downward and westward to Beta (8). 

We have already noted the first-magnitude star 
FoMALHAUT [331]—directly to the south. A little to 
the west, and just above, is the constellation CAPRICOR- 
NUS, the SEA-GOAT [75], with stars so faint as to be almost 
invisible except upon a clear night. We may always 
find its location, see p. 28, by remembering that the 
“shaft of Altair’’-—the three stars, Alpha (a), Beta (B), 
and Gamma (y) of AguILA [20]—points downward 
directly to it, just as it points upward in the general 
direction of Lyra, the Lyre [260]. We have already 
spoken of SAGITTARIUS [340], on p. 56. Above ALTAIR, 
as it sinks to westward, we find the small constellations, 
DELPHINUS, the DOLPHIN [155], and SAGITTA, the ARROW 
[335]; and higher, and farther to the north, is CyGNuUs, 
the SWAN [145], marking the Northern Cross. 


But, as shown on p. 28, the shaft of ALTAIR—the three 
stars Alpha (a), Beta (B), and Gamma (y) in AQuILA— 
does not point so directly downward as shown above; 
it now lies more nearly parallel to the horizon. Upon 
the other hand, the Northern Cross and SaGiTTa do 
point downward more directly. Of Lyra [260] we have 
just spoken, p. 58, under our northward map. The 
remaining constellations toward the west are now too 
low in the sky for clear observation. The track of the 
planets lies in our present map through SAGITTARIUS, 
CAPRICORNUS, AQUARIUS, Pisces, ARIES, and TAURUS; 
see p. 80. At precisely this hour, in northern latitudes, 
the first of these has set; see note 10, p. 31. 


for Opera-Glass, field-Glass, and Telescope 61 


Yoft/ 

ee AND. 
e 2 

KB 


i 
TRIANGULU 
SS 


Star Magnitudes 
O51 @2nd031rd*4the5th and under 
OCluster or Nehula. 


i 
eeancie 


KEY-MAP TO THE SKY AS THE OBSERVER FACES SOUTH. 


NOV. 1, 8 P.M., OCT. 15, 9 P.M., 


eh 
3 


5 oe e 
PISCIS AUSTRINUS 


OCT. 1, 10 P.M., 


Dene 
LACERTA CX 


- 7 
e ° ye . 
<6 we Gace ” 5 oe 
7 LYRA 
: a 
e Z 
e 


VULPECULA HERCULES__ 
O/127 95 
e 


7 5 
SAGITTA 


e e 


OPHIUCHUS. 
a 

“ 

7 


SERPENS 


. 
O“N/7 
Onz4 
O/720 
118 


ynalhaue 


As the observer faces Soulhward 
y the stars athislett are 015119); 
those at his right are setting. 





SEPT. 15, 11 P.M., SEPT. 1, 12 P.M. 


FOR NIGHT-CHART TO THIS MAP SEE OPPOSITE PAGE, 
FOR THE SKY AS THE OBSERVER FACES NORTH, SEE PP. 58, 59. 
For the sky at other Dates and Hours see Time Schedule, p. 35. 


The Telescopic Objects. 


For the Constellations See the Page Opposite. 


The numbers in brackets [ ] refer to corresponding numbered notes in Observer’s Catalogue, p. 116. 


I. WITH OPERA-GLASS OR FIELD-GLASS first examine 
the course of the Milky Way, lying here to the westward, 
at the right, and running from CyGNus at the northwest, 
southward through SAGITTA, AQUILA, and SAGITTARIUS. 

It will be interesting, also, to trace out the pretty 
chaplet of small stars formed by Theta (8), Gamma(y), 
Lambda (A), etc.,in Pisces. It isnow almost due south, 
upward and a little to the left from the bright star 
FoMALHAUT. ‘Trace, also, just to the right of this 
pretty figure, the little Y in AQuARIUS, which forms the 
mouth of the water jar. 

Among the double stars that may be divided by an 
opera-glass or field-glass are Alpha (a) [76] and Beta (B) 
[77] in CAPRICORNUS; and also the star marked 6 [426] 
near the foot of the Cross in CyGnus. Of the easier 
double stars in Lyra, and of the PLEIADEs in TAuRUS, 
we have spoken on p. 59, in connection with the northward 
sky. Among the smaller groups here before us, DEL- 
PHINUS and SAGITTA will be found of special interest. 


Il. WuITH A TWO-INCH TELESCOPE first note, with 
eye-piece of lowest power, the objects already mentioned. 
Sweep through the rich sections of the Milky Way, 
especially in the neighborhood of ALTAIR [21] and down- 
ward toward the west, past the Lambda (A) of AQuILA 
and the Lambda (A) of SAGITTARIUS. 

Among the double stars there is a fine object for a 
two-inch telescope in the Beta (R&) [332] of Piscrs Aus- 
TRINUS, low down but now almost directly before us to 
the south. An easy and beautiful double is the Gamma 
(y) [157] of DELPHINUS; and even finer is the Beta (B) 
{147] of CyGnus. But of this, and of the stars in Lyra, 
we have just spoken on p. 59. Turning now to the east, 
or toward the left, beautiful objects are to be found in 
the Gamma (y) [32] and Lambda (A) [31] of ArrEs, and 
in the Pi (a) [4] and the Gamma (y) [3] of ANDROMEDA,— 
though the latter are rather high for convenient study. 
Among the faint stars of Pisces we may try Alpha (a) 
[321] and Psi (W) [323]; and in AQuaARIUs we shall find a 


charming object in Zeta (£) [17], the components being 
practically of the same magnitude. Note, also, the star 
Psi (’) [18] in the same constellation. 

Turning again to the westward, or to the right, we 
may note one of the most beautiful of the double stars 
in the Theta (8) [368] of SERPENS. Though the actual 
slant or inclination of the lines here at the map’s edge 
varies from the chart, the imaginary line from Zeta (¢) 
to Lambda (A) in AQUILA really leaning to the right, yet 
the permanent alignment of thestars is always unchanged. 
About half-way between these stars, therefore, the Theta 
(®) of SERPENS will still be found. 


III. WuTH A THREE-INCH TELESCOPE, first examine the 
objects listed for the two-inch instrument. Using an eye- 
piece of low power, examine, next, the clusters marked 
M 2 [16] in Aquarius; M 15 [303] in PEGAsus—in line 
with Theta (®@) and Epsilon (€); M 11 [23] in AQUILA— 
near the star Lambda (A) in the Eagle’s tail; and M 27 
[427] in VULPECULA, almost in line with Beta (B) at the 
foot of the Northern Cross and the Eta (yn) of SAGITTA. 
Among the finest is M 33 [396] in TRIANGULUM; but this, 
as well as the great nebula in ANDROMEDA, M 31 [2], is 
now rather high up for convenient observation. 

Among the double stars are Pi (1) [79] and two near-by 
stars [78, 79b] in CAPRICORNUS. This group of small 
double stars is fully charted in the map of the N. Hemi- 
sphere at the location assigned in the Observer’s Catalogue 
[79], etc. Higher up is the Epsilon (€) [302] of PEGAsus, 
and to the eastward is the star Zeta ({) [322] in PIscCEs, 
the small object between Mu (p) and Epsilon (e). It is 
the fourth of the little stars on the westward line from 
Alpha (@). We may also try Gamma (¥) [333] in Piscis 
AUSTRINUS. In CETUS, we may examine Alpha (@ 
[111], Gamma (y) [112], Zeta (€) [114], and the small 
star marked 66 [116]. The last offers a fine con- 
trast of colors, but in searching for the star it is well 
to remember that Omicron (0) [113] is a remarkable 
‘“‘variable,’”” and is often invisible to the unaided eyes. 


UW. Objects to be Seen: The Solar System 
THE SUN 


WE frequently refer to starlight and sunlight as though they were different things. 
Strictly, however, the only light that we know anything about, on any large and important 
scale, is starlight; for the Sun itself is, as we have seen, a star; and thus all the light of the 
day is starlight. The Sun is but the nearest of the stars. 

And the lights of the night are starlight, except the artificial lights that men have 
made. ‘The moon shines not by its own light but wholly by the reflected light of the Sun. 
The planets shine, also, chiefly by reflected light. If Jupiter and Saturn be partly self- 
luminous, as some suppose, their brightness would be insignificant without the Sun. Even 
the chance comets that come into our skies, while they yield a partial glow of their own, 
shine chiefly by their reflection of the Sun, or because of the direct action of the Sun upon 
them. The ‘‘fixed’’ stars shine by their own light, for these—as we have seen—are other 
suns, many of them far larger and more luminous than ours. 

Our Sun, however, is of even greater importance than all the other stars together, for 
the Sun gives us heat as well as light. This heat gives us not only the warmth which 
prevents the solid freezing of all living things, but it gives us our changes of the seasons, 
our clothing, and our food. ‘There could be no vegetation without the stimulation afforded 
by the Sun’s warmth; and without vegetation no animal life could be supported. The 
light received from the Sun is 600,000 times that received from the moon, and it is roughly 
estimated that the apparent brightness of the Sun’s surface is about 150 times that of a 
calcium light. The heat of the Sun is so far in excess of any standard which we can secure 
that its very expression becomes difficult. Estimates vary. Said the late Prof. C. A. Young 
of Princeton University—in quoting one of the best authorities on the subject—its “‘‘ effec- 
tive temperature’ comes out about 7000° C., or 12,000° Fahrenheit.” ‘‘Or,’’ says Professor 
Young himself—in illustrating the solar radiation at the Sun’s surface—‘if a bridge of ice 
could be formed from the earth to the Sun by a column of ice 2.1 miles square and 93,000,000 
miles long, and if in some way the entire solar radiation could be concentrated upon it, it 
would be melted in one second, and in seven more would be dissipated in vapor.”’ 

But of the light and heat sent out by the Sun, the earth receives only sm@amaoth part. For 
the earth is not only a very small body as compared to the Sun; it is, also, very far distant. 
These factors in the case are difficult to realize, if merely set down in figures. Let us, there- 
fore, fall back on some familiar comparisons. The Sun is 1,300,000 times larger than the 
earth. A railway train that could make the circuit of the earth in 30 days would take over 
85 years to make the journey round the Sun. If 109 globes as large as the earth were put 
edge to edge and if the surface of the Sun were flat, their long line would just reach across 
the Sun’s face. When we look at our moon it is hard to realize that it is about 240,000 
miles away. The diameter of the circle it describes is thus approximately 480,000 miles. 
Yet the Sun is so large that the moon could revolve in its orbit, if earth and moon were 
put zmside the Sun, and there would be much room to spare, for the real diameter of the 
Sun is over 866,000 miles. 

62 


THE SUN AT TOTAL ECLIPSE 


Showing corona and prominences; from a photograph taken, Jan., 1808, at Jetir, India, by Dr. W. W. Campbell, Director of the 
Lick Observatory 


63 





64 A Beginner's Star=Book 


The facts as to the constitution of the Sun are of great interest, but their full descrip- 
tion belongs to a manual of astronomy rather than to a simple manual of observation. 
To the beginner the chief objects of interest on the Sun’s surface are the sun-spots and 
the facule. The sun-spots have usually been regarded as cavities or holes in the photo- 
sphere,—the photosphere is 
the cloud-like covering of in- 
tensely heated matter which 
enfolds the Sun’s_ surface. 
The faculeé are best seen near 
the Sun’s limb, the ‘‘limb”’ 
being the edge of the disk, but 
they are found like streamers 
or ridges of intenser light over 
the whole surface of the Sun; 
they are especially active in 
the region of the sun-spots. 
They are from 1000 to more 
than 40,000 miles in length 
and from 1000 to 4000 miles 
broad. The faculez should not 
be confused with the promin- 
ences or protuberances, which, 
when eruptive in nature, shoot 
like the spray of colossal fountains to heights of from 100,000 to over 300,000 miles. The 
velocity of their outward rush is in some cases as high as 600 miles a second. These may 
usually be seen only with the aid of the spectroscope; see Fig. 10, p. 68. They may also 
be observed and photographed during an eclipse of the Sun; see p. 63. Even a small 
telescope, however, will show us the facule and the sun-spots. The latter are the more 
interesting and the more easily observed. 

Warning must at once be emphatically given against any attempt to view the Sun 
without some special protection for the eye. Three methods are available. A small 
protective cap of dark-colored glass, sometimes called a ‘“‘sun-glass,’’ is usually provided 
with one of the astronomical eyepieces. This may be safely used, in directly viewing 
the Sun, on instruments as large as three inches in aperture, provided the telescope is turned 
away from the Sun at frequent intervals. Such a precaution is necessary not only to spare 
the eye, but to prevent the heat of the Sun from cracking the eyepiece. These small 
sun-glasses may also be used on larger instruments but with a risk proportionate to the 
increase in size of the telescope. More than one astronomer has lost an eye by taking 
injudicious risks in solar observation. A special attachment, called the “‘Herschel”’ 
eyepiece, much reduces both risk and inconvenience. In this way the Sun’s rays are 
reflected at right angles by a plane of unsilvered glass, most of the light and heat passing 
harmlessly out of the open end of the device. While this method greatly decreases the 
amount of heat and light reaching the eye, there is still need for the protecting cap of darkly 
tinted glass over the eyepiece proper. The glass need not now be so dark, however, as 
when the Herschel attachment is not employed. 

By far the best method for observing the Sun and for properly following the spots is 
shown in Fig. 5. This is not intended as a formal design, but merely as the general sug- 
gestion of a method. It may be elaborated or simplified according to the size of the tele- 





Fig. 5. Projecting the Sun's Image on Screen. 


The Sun 65 


scope and the resources of the observer. The square G H is merely a cardboard shield 
slipped over the telescope to prevent the direct rays of the Sun from obscuring the image 
projected on the screen, A B C D. The rods supporting this screen may be of bamboo 
cane, or stiff wire. The collar at K N should be free enough to permit the frame to be 


N Ss N 


Ss N Ss 
Fig. 6. Orientation of the Sun’s Image. 


At left, as seen with naked eye; at centre, as seen in astronomical telescope; at reader's right, as seen when projected on a screen. 


moved a little up or down on the tube of the telescope. An approximate focus may be 
obtained by merely holding a white card behind the telescope, moving the eyepiece E 
a little in or out as required. If the frame disturbs the balance or poise \ 


of the telescope on the tripod, a make-weight may be hung on the large 
end of the tube; or the tube, between N and GH, may be rested on the 
back of a chair. The image of the Sun may be shown more clearly ifa 5 ha 


dark cloth be thrown over the top and the farther side of the screen, 
ABKD. The image may then be viewed from this side of the screen. 
The sun-spots may not only be well seen, and drawn and recorded for 


future comparisons, but a number of observers may view them at the 
same time,—if there be any spots there! A sun-spot maximum will occur 
in the year 1915, and thereafter at intervals of 11.13 years. They are E W 


Dene 


likely, however, to be present at any time; but they are not always 
present, and if the telescope does not show them, it is not necessarily the 5 
fault of the instrument. They may sometimes be seen with the unaided 
eye, either near the time of sunset, or, during the day, through a large piece 
of colored glass. The observer may always know that any spots that can 
be seen with the naked eye are at least four times the size of our earth. & 

As the Sun, like the earth, has “points of the compass,”’ it is well for 


us to note these at once. They are here shown in Fig. 6—the disk to the 
reader’s left representing these directions as they are, or—in other words 


—as they appear when the Sun is viewed with the naked eye or in an 
opera-glass. The central disk shows these directions as they appear in a 
telescope with astronomical eyepiece; the disk to the reader’s right shows E W 


jane 5 


the Sun as it appears through such an eyepiece when the image is pro- 

jected on a screen, as in Fig.5. From Fig. 7 we may see that the axis of 

the Sun is sometimes tipped a little to right or left, as we face toward it, Sept. 5 

and that the path of the sun-spots shows a somewhat different inclina- 7" 7,,Couse of Me 
tion at different periods of the year. The observer should bear in mind 

that the Sun is shown in Fig. 7 with the image “‘erected”’ or as viewed with the naked eye. 
Fig. 6 will therefore show how to make the required mental adjustment for the astronomi- 
cal eyepiece, whether the image be viewed directly or projected on a screen. 


66 H Beginner’s Star-Book 


As we note the course of the sun-spots, we seldom find them exactly at the Sun’s equator 
or near the poles. They are usually seen in the regions lying midway between the poles 
and the equator, coming into view at the eastern limb (our left as we face southward), 
passing out of view at the right in about fourteen days, and sometimes (after as long an 





FIG. 8. THE DISK OF THE SUN 


Comparison of direct photograph, at reader’s right, with high-level spectroheliogram, on left 
From negatives made at the Yerkes Observatory 


absence) reappearing at the eastern limb. We can thus prove to our own satisfaction 
that the Sun rotates on its axis, as does the earth, and that its period of rotation is approxi- 
mately twenty-seven days, as viewed from the earth. The period of rotation is a little shorter 
near the Sun’s equator than to the north or south of it, for the gaseous masses of which 
this great whirling globe is composed seem to move somewhat more slowly as we look 
toward the poles.* In our engraving marked Fig. 9, we can trace the course of a group 
of spots across the Sun’s disk; and in the upper half of the sections which compose that 
illustration we may trace the life of a sun-spot as it grows in magnitude. In Fig. 8, in the 
image to the reader’s right, the dark centre of the spots (note, for example, the largest 
spot there shown) is called the umbra (or shade); the half-shade that seems to bound 
the umbra is called the penumbra; within the umbra there may sometimes be seen a still 
darker ‘‘core’’ called the nucleus. The expressions ‘‘dark”’ and ‘‘darker” and ‘“‘shade’”’ 
are used, of course, only in a relative sense; for the very darkest spot on the Sun is always 

* Not only has the Sun, like the earth, a motion on its axis, but it has a motion in space. Ata velocity of about 
12 miles per second (over 720 miles a minute) it is carrying the whole solar system in the general direction of the bright 
star Vega (see p. 38). This point is called ‘‘the apex of the Sun’s way.’’ The conclusions as to the direction of the 
Sun’s motion have not been invalidated by the investigations of Kapteyn, as some text-books assume; for while Kap- 
teyn and others have shown the possible existence of a double star-drift, the new facts have been found to lead sub- 
stantially to the old conclusion. There has always been some slight disagreement among astronomers as to the 
precise direction represented by the “ apex,”’ but all these estimates place the point fairly near the star Vega. The 
exact position according to Boss (1910) is R. A. 18 h. 2 min.; D.+34°; according to Hough and Halm, Rr. A. 18 he 
4 min.; D. + 26°. For recent expressions on the direction of the Sun’s motion, the advanced student may wish to 
refer to British Ass. for the Advancement of Science; President’s Address, 1907, by Sir David Gill, K.C.B., LL.D., 
F.R.S., etc., p. 19; Newcomb-Engelmann, Pop. Astron., 4th edition, ed. by Prof. Dr. P. Kempf, of the Astrophysical 


Observatory, Potsdam, pub. Leipzig, 1911, p. 535; and especially to Les Courants Stellaires, par M. P. Puiseux, 
Astron. de l’Obs., Paris, Président de la Société Astronomique de France; Bulletin dela Soc. A. F., July, 1911, p. 303. 


The Sun 67 


brighter, by many times, than any light we can create by artificial means. The umbra 
of a sun-spot, if a very small one, may be 500 or 600 miles in diameter; the diameters of 
the larger ones are from 30,000 to 50,000 miles; and the penumbra surrounding a group of 
spots is sometimes 100,000 miles in width. Note also in Fig. 8, the image on the reader’s 





FIG. 9. SHOWING DEVELOPMENT OF SPOT AND ROTATION OF SUN 
From spectroheliograms made at the Yerkes Observatory 


left. Here we have a picture of conditions at a higher level of the Sun’s atmosphere than 
shown on the right, but at the same moment. We note the same spots, but the spectro- 
heliograph enables us to see near them the brighter clouds of calcium vapor called the 
floccult. ‘These lie above the facule, see p. 64, and seem to arise from them or to crown 
them—as white crests will often crown the waves of a stormy sea. 

In one case the lifetime of a sun-spot was eighteen months (1840-41) but the period 
of duration, even for large ones, is usually from two months to three, and they sometimes 
persist for only a few days; though a new spot may sometimes break out in the same quarter 
of the Sun from which a spot has disappeared. An active spot will often exhibit marked 
changes within as short a period as twenty-four or thirty-six hours, and simple drawings 
which exhibit the state of such an object from day to day become interesting and useful 
records. 

The corona is visible only at the time of the Sun’s total eclipse by the moon. This, 
as may be seen by the photograph reproduced on p. 63, is a beautiful halo or glory com- 
pletely surrounding the solar sphere. At the edge of the Sun’s disk, during such an eclipse, 
the prominences may also be seen—shooting like brilliant sheets or tongues of flame up 


68 H Beginner's StareBook 


into the light of the corona. As eclipses of the Sun recur very infrequently at any 
particular point, and as the breadth of the shadow at totality averages only about 70 
miles, they may be regarded as rare phenomena. Expeditions are sent great distances for 
the purpose of observing them. 





FIG. 10. ERUPTIVE PROMINENCE AT THE SUN'S LIMB 


From negative made at the Yerkes Observatory 


One reason why it is so hard for us to appreciate the great size of the Sun is that 
the Sun’s actual distance from us is so great. We call it roughly 93,000,000 miles. But 
what do such figures mean? Says Professor Holden, formerly of the Lick Observatory, 
“Sound travels fast. It takes time; you see the flash of a distant gun before you hear the 
report. It travels 1100 feet a second. ... But, if a sound were made in the Sun, and if 
a sound could travel through the empty spaces where there is no air (which it cannot 
do), it would not reach the earth till fourteen years afterward. If a cannon-ball could be 
fired in the Sun straight at the earth, you would first [in 8.3 minutes] see the flash [except 
that the brilliancy of the sun would prevent]; nine years afterwards the ball would reach 
the earth, and five years after that you would hear the sound.’’* Indeed, if an infant 

* For the popular and yet scientific statement of the facts as to the distance, dimensions, and constitution of the 
Sun, see the volumes by Young, Todd, Lockyer, and Holden named in the bibliography on p. 144. See, also, A Study 


in Stellar Evolution, G. E. Hale, University of Chicago Press, 1908; and The Sun, by Charles G. Abbot, Director 
Smithsonian Astrophysical Observatory, D. Appleton & Co., 1911. 


The Moon in the Telescope 69 


could put out his hand to-day and touch the Sun—assuming that his arm were as long 
as the distance between Sun and earth,—he could never feel the pain the heat might give, 
for he would die of old age before the nerves, despite the high rapidity with which they 
transmit sensations to the brain, could report the fact of contact. More than 100 years 
must elapse for the transmission of the message. If, over distances so great and under the 
difficulties imposed by the Sun’s light and heat, the beginner cannot add greatly to his 
stock of knowledge, there is little reason to complain. The wonder, rather, is that we 
may learn so much; and that even with the smallest instruments we can so readily 
prepare ourselves for further study. 


THE MOON 
OUR NEAREST NEIGHBOR 


We now pass to what is perhaps the most interesting and charming of all the objects for 
a small telescope. The moon’s diameter is 2162 miles, about one-fourth the diameter of 
the earth. As its distance from us is but 240,000 miles, a magnifying power of 60 will be 
sufficient to diminish its apparent distance to 4000 miles. From two to three hundred 
different features upon its surface can thus be brought into clear 
relief, and the use of still higher powers will reveal an even greater 
measure of detail. The lunar ‘“‘seas,’’ ‘‘craters,’’ and mountain 
ranges may be studied, even by the veriest novice, with real 
satisfaction. 

First, however, let us remember that even for the unaided 
eyes, the moon is a far finer and lovelier object than we usually 
realize. Instrumental aid, whether opera-glass, field-glass, or 
telescope, should not destroy the interest of the moon as it 
appears to our ordinary vision. Indeed, this interest should be 
thus increased. The use of instruments may help us to see more 
freely and clearly the objects on the moon’s surface, but when these are once known, 
the naked-eye moon should become more fascinating than before, for we can now 
identify many of the objects that we should probably not have noted at all. Instead of 
merely watching for the fantastic shapes of the Man in the Moon, the Lady in the Moon, 
the Rabbit in the Moon, etc., etc. (all very harmless and amusing occupations), we can 
learn increasingly to recognize the larger shapes and outlines of actual lunar formations. 
The moon’s “‘geography”’ is easily acquired. Indeed, the eye may readily be trained to 
recognize some of its bolder features even by daylight. It was this use of his natural 
mental and optical equipment that enabled Leonardo da Vinci—painter, architect, engineer 
—to reach the true solution of “‘the Old Moon in the New Moon’s Arms.”’ He discovered, 
more than a hundred years before the invention of the telescope, that the faint soft light 
thus seen on the surface of the old moon was the result of illumination from our earth itself. 

For the moon is not self-luminous. It shines by reflected light alone. This reflected 
light is chiefly that of the Sun. Here in our small illustration, the brighter light comes 
therefore from the Sun, and, striking the globe of the moon from the west, makes the bril- 
liant crescent shape called the ‘‘new’’ moon. This, from our viewpoint, is the lunar sun- 
rise. As the period of the moon’s revolution in its orbit round the earth is exactly coincident 
with the period of its revolution on its axis, the same side is always turned toward us. But 





Old Moon in New Moon’s Arms 


70 fH Beginner's Star-Book 


upon this side, we may see the increase of the lunar day as the Sun’s rays light up more and 
more of the moon’s surface. In the illustration on p. 73 we may see the advance of the Sun 
at 2 days; on p. 75 the Sun’s advance at 6 days; on p. 77 at 934 days; on this page at 14% 
days. Here, the moon is said to be full. During the latter half of the month, the 





THE MOON AT FOURTEEN AND ONE-HALF DAYS 
Image erected; for Study with Opera-Glass or Field-Glass, or with Telescope using Terrestrial Eyepiece 


side of the moon toward us catches daily a little less of the Sun’s light, the long lunar sun- 
set begins, black night falls upon the ‘‘sunrise side’’—the side to the observer’s right,— 
and the objects which were lighted from the west now seem to be lighted only from the east. 

We can see at once, moreover, that while the full moon represents the phase of most 
brilliant illumination, it shows us less detail than we find in our other illustrations. This 
is because the Sun’s light now strikes the moon directly. Weare enabled to see the objects 
on the moon at their best, only as they are brought into clear relief by their shadows, 
and we see the full moon so imperfectly because in the Sun’s direct illumination the shad- 
ows are largely destroyed. Still, there are obvious distinctions and contrasts, at least for 
the larger features, and we are certainly enabled to get a simple general view of the whole 
earthward side. I have therefore chosen this view of the moon for our first study. The 
image is here presented as viewed with the naked eye, the opera-glass, field-glass, and spy- 
glass,—or through the telescope, if used with a terrestrial or erecting eyepiece. 

Upon the moon as here shown, we may first note that certain tracts or areas are much 
darker than others. These darker spaces, as we may see even in an opera-glass, are depres- 
sions in the moon’s surface, lying somewhat lower than the surrounding region. They were 
called “‘ Maria” or ‘‘Seas’’ by Galileo and were among the objects first shown to the poet 
Milton at the time of his visit (1638) to the Italian astronomer.* They contain no water, 


*«. . the Moon, whose orb 


Through optic glass the Tuscan artist views 
At evening from the top of Fesolé, 
Or in Valdarno, to descry new lands, 
Rivers or mountains in her spotty globe.” 
MILTON, Paradise Lost; Book I. 


The Moon in a Ficld-Glass 71 


for the moon has no water and practically no atmosphere, but the early name has been 
preserved. They are large, low-lying, gray plains, here and there marked by ridges and 
small crater-like formations. The one which is most perfectly enclosed is marked A in 
the Key-Map. This is Mare Cristum—the Sea of Crises, or Sea of Conflicts; dimensions 
about 70,000 square miles; 280 miles long; 360 miles wide (east to west). The latter 
dimension seems the smaller in a telescope,—this is an optical illusion, due to foreshorten- 
ing. The object marked B is the Sea of Fecundity,— Mare Fecunditatis; that marked C 
is the Sea of Nectar,—Mare Nectaris; D is the Sea of Tranquillity,—Mare Tranquillitatis; 
E is the Sea of Serenity,— Mare Serenitatis; F is the Sea of Showers,—Mare Imbrium; H is 
the Sea of Storms,—Mare Procellarum; N is the Sea of Clouds,—Mare Nubium. These 
“seas,” particularly A, B, D, and E, may often be distinguished with the unaided eyes. 
The Sea of Conflicts (A) may sometimes be clearly seen by daylight. As the moon is here 
shown, this object lies nearer the top of the picture than is usually the case. Compare its 
position as shown on pp. 73, 75, 77. Note, however, that in these the moon’s image is 
inverted, for study with an astronomical eyepiece. 

Let us now note some of the larger mountain ranges. The longest and most impressive 
is No. 57, the Apennines,—bordering the Sea of Showers. Just above, and across the strait 
between F and E, the range marked 59 is called the Caucasus Mountains; and to the 
left, the Alps are numbered 60. Near them, at No. 56, is a great walled plain called 
Plato, 60 miles in diameter. No. 55 is the Bay of Rainbows,—Sinus Iridum, one of the 
most beautiful features in the ‘‘coast-line’’ of the Sea of Showers. 

The most conspicuous of the great lunar ‘‘craters’’—so called on account of the vol- 
canic appearance of their structure*—are Tycho, No. 50; Langrenus, No. 4; Copernicus, 
No. 51; Kepler, No. 52; Aristarchus, No. 47; and Grimaldi, No. 54. Because of the direct 
illumination of the Sun, these are now visible chiefly as brilliant patches of light—Aris- 
tarchus is the brightest spot on the moon, Grimaldi the darkest—but in our other maps we 
may see some of them under different illuminations. From the region near Tycho, No. 
50,—which Webb calls ‘‘the metropolitan crater of the moon,’”—radiates the most con- 
spicuous of those systems of light-streaks or light-rays which have proved such an insol- 
uble problem to the astronomer. They give to the moon at this time what some one has 
called the appearance of a “peeled orange.’’ We refer to them again on pp. 74, 78. 

Grimaldi, No. 54, is one of the largest of the ‘‘wall-surrounded”’ plains, extending 148 
miles N. to S. and 129 miles E. to W., covering about 14,000 square miles. Kepler, No. 
52, is also a ring-plain, though smaller—about 22 miles in diameter—and very much 
brighter. A peak on its eastern border attains a height of 10,000 feet. Brighter still is 
Aristarchus, No. 47;—so brilliant, indeed, that it may often be seen long before the fer- 
minator reaches it, shining like a faint but obvious beacon in the waste of the lunar night. 

The terminator is the division-line between light and darkness on the moon’s surface. 
The advance of the terminator marks the progress of the lunar day. The moon when 
full shows, of course, no terminator, but in our illustration of the moon at two days— 
shown on the next page—it has advanced just beyond A, the Sea of Conflicts. There be 
careful to note that we show the image of the moon inverted, as seen in a telescope with an 
astronomical eyepiece. The object A seems, therefore, to be low down to the left instead 

* Next after the ‘‘seas’’ and mountains, the larger lunar formations, especially those having an appearance suggest- 
ing volcanic origin, are called walled plains; the deeper of these—smaller, more definite, and more circular in form— 
are called ring-plains; and the ring-plains are also often called craters. These terms are all applied with a good deal 
of freedom; inasmuch as the real origin of the formations is still a mystery. The objects on the moon were named 


largely by Riccioli (1651), in honor of various personages, astronomical and otherwise—as ‘‘Copernicus,”’ ‘‘ Kepler,’’ 
etc. Some of this terminology is utterly fanciful and has no excuse for existence except that it is established. 


72 fH Beginner's Star=Book 


of upward to the right; and in dealing with the lunar objects from this point onward the 
directions, etc., will be given for the moon as so viewed and as so represented in our larger 
engravings. The later of these are clearer in detail than the present, for the very 
new moon lies too near the horizon for sharp definition. Its objects show far more distinctly 
in a small telescope than in 
this photograph. Of the Sea 
of Conflicts (A) we have al- 
ready spoken, p. 71; but we 
may now note within it two 
or more small craters. One 
of these, No. 1, is called 
Peirce. Another, larger, 
crater is called Picard, 
Nol )2; and as22temuiles:in 
diameter, with a small cen- 
tral mountain. On Firmi- 
cus, No. 3, have been noted 
slight periodical changes 
which to some have sug- 
gested vegetation; doubtful. 
Firmicus is the lower of the 
two small formations faintly 
shown in the photograph. 
Upward from it, slightly to 
the right, is Apollonius. 
Both are ring-plains. Lan- 
grenus, No. 4, is a superb 
walled plain, with walls from 
8000 to 10,000 feet high, 
enclosing an area 90 miles 
long by as many broad. Its 
central peak rises to a 
height of more than 3000 
feet. Vendelinus, No. 5, is KEY-MAP TO THE MOON, AT TWO DAYS 
not so sharply outlined in See accompanying text, with illustration opposite 
our photograph, its walls being lower and its formation more irregular, but it covers an 
area almost as large. Petavius, No. 6, is even larger than the preceding. The smaller 
formation at the right is called Wrottesley; and on this side the border of Petavius rises 
to 11,000 feet. A deep sharp cleft running from almost the centre of Petavius upward 
toward the right seems to have been first noted by the German observer, Schroeter, Sept. 
16, 1788. One peak of the central mountains here reaches a height of 6000 feet abové 
the floor. Snellius (No. 7) and Stevinus (No. 8) are also ring-plains, the former 50 miles 
in diameter, the latter a little larger—though showing smaller in our photograph. In 
Furnerius, No. 9, we have another walled plain almost as large as Langrenus, though more 
irregular in form. 

Returning to the region of the Sea of Conflicts (A) we note to the north (remember 
that in our map south is above, north below, as in an astronomical telescope) the fine for- 
mation called Cleomedes, No. 10. It is oblong in shape, about 78 miles in diameter, and 





The Moon in the Telescope 73 


its huge walls rise from 8000 to 10,000 feet above the floor. Just below, No. 11, is Burck- 
hardt, 35 miles in diameter, chiefly characterized by the great relative height of its eastern 
wall (observer’s right), which rises to nearly 13,000 feet. The objects Nos. 12 and 13 are 
two ring-plains called Geminus and Bernouilli, the former being the larger, with a di- 
ameter of 54 miles. Mes- 
sala, No. 14, isnot so clearly 
marked, its roughly circular 
border being very irregular; 
its diameter is about 70 
miles. Even larger, how- 
ever, is No. 15, Endymion, 
one of the most clearly 
marked of the walled plains 
in the very young moon. 
Its great walls are crowned 
by superb peaks, attaining, 
in some instances, heights 
of 10,000, 12,000, and 15,000 
feet. In following the ‘‘ge- 
ography” of the moon with 
the aid of direct photo- 
graphs, the author wishes it 
were possible to present a 
photograph for each hour 
of the moon’s age. But the 
limits of space demand a 
selection at wider intervals. 
The illustrations have been 
so chosen, however, as to 
indicate all of the more im- 
portant formations. For the 
beginner this is sufficient. 
Indeed, the multiplication 
THE MOON, AT TWO DAYS of detail—just at the first 
Image Inverted, as in Astronomical Telescope; see Key-Map opposite 16 confusing rather than 
helpful. Most of the objects shown in our picture of the moon at two days may be seen 
quite as well—in some cases even better—on the third and fourth days, and yet again in 
the lunar sunset when the moon is old, the light then striking these objects at quite another 
angle. The illustration of the moon at six days will serve fairly well not only for the fifth 
and sixth days but for several days thereafter; and when this ceases to be sufficient that 
for the moon at nine and three-quarter days will begin to be of service. This will in turn 
be sufficient, for all ordinary purposes, till the chart of the full moon, p. 70, is more appro- 
priate. The use, there, of the terrestrial eyepiece to which that photograph is adapted, is, 
for the beginner, a positive advantage. For as the moon becomes fuller and brighter the 
additional lenses of the erecting eyepiece serve to cut down the excessive light. 
Theophilus, Cyrillus, and Catharina—shown so finely as objects 30, 31, 32 in the six- 
day moon—appear again, and quite as strikingly, in the moon at 18 and 19 days; but the 
““old’”’ moon rises late. 





74. H Beginner’s Star-Book 


We have already spoken of the lunar seas marked A, B, C, D, E, and of the other 
formations from No. rt to No. 15. Nos. 16 and 17, not far from the border of 
the Sea of Conflicts (A), are called Proclus and Macrobius. The former is, next to 
Aristarchus,—No. 47, see p. 7I—the brightest object on the moon’s surface and the 
apparent centre of a small 
but brilliant system of light- 
streaks such as we find at 
Tycho and Copernicus. “A 
close examination of our 
photograph will show these 
radiations extending into A. 
Macrobius is less brilliant 
and therefore more clearly 
seen; diameter 42 miles, 
border 13,000 feet above 
the floor. Lower still in 
our picture is the fine pair, 
Nos. 18 and 19, called Atlas 
and Hercules—very boldly 
marked and easily observed. 
Atlas is 55 miles and Her- 
cules 46 miles in diameter; 
the altitude of the enclos- 
ing borders is in each case 
about 11,000 feet. In the 
ring-plains, Eudoxus, No. 
20, and Aristotle, 21, we 
have a Vpairpestill. Gner. 
Their diameters are, re- 
spectively, 40 and 60 miles, 
and their bordering walls 
also reach heights of about 
11,000 feet. As to Aris- 
totle, Elger says, “The 
formation presents its most KEY-MAP TO MOON, AT SIX DAYS 
striking aspect at sunrise, See accompanying text, with illustration opposite 
when the shadow of the west wall just covers the floor, and the brilliant inner slope 
of the east wall with the little crater on its crest is fully illuminated.’’ Almost on a 
direct line between Nos. 20 and Ig lies No. 38, Burg—only 28 miles in diameter but 
with a brilliant interior mountain. The two other small, sharply defined ring-plains 
above and to the left of Burg are Mason and Grove. To the right of Mason, in duller 
outline, is Plana. On the very border of the Sea of Serenity (E) lies the superb walled 
plain Posidonius, No. 22,—often better lighted in the six-day moon than in this photo- 
graph,—and next to it, Chacornac, No. 23. Posidonius is one of the finest of lunar objects, 
for while its walls are only abo. 6000 feet high, its central crater rises from a brilliant 
floor on which, with a good instrument, one may find the remains of an older rampart. 
Between No. 24 and No. 25, Pliny and Vitruvius, seems to flow the broad strait which 
unites the Sea of Serenity (E) with the Sea of Tranquillity (D). Pliny is 32 miles in di- 





The Moon in the Telescope 15 


ameter, Vitruvius 19. The small ring-plains, Kant (26) and Maedler (27), lie to the east 
and west respectively of Theophilus, No. 30. 

Theophilus, 30; Cyrillus, 31; and Catharina, 32;—this triple group forms one of the 
really magnificent spectacles of the moon. When the moon is 514 to 714 days old, or 
when 18 to 20 days old, they 
may be clearly distinguished 
even by a small spy-glass or 
field-glass, if the glass be 
steadily held. Of these great 
ring-mountains Catharina is 
largest in area, its diameter 
being over 70 miles from 
N.toS. Cyrillus is chiefly 
marked by the narrow pass 
which opens outward toward 
Catharina. Theophilus is 
the deepest of the three— 
probably the deepest on the 
moon—being enclosed by a 
rampart which rises at one 
point to 18,000 feet. Its 
diameter is 64 miles. Its 
fine central mountain covers 
an area of 300 square miles 
and rises to a height of 6000 
feet above the floor. 

No. 28, Fracastorius, now 
opens like a great bay at the 
shores of the Sea of Nectar 
(C); but it is apparently the 
remains of an older forma- 
tion, a ring-mountain now 
destroyed. Piccolomini, 
No. 33, is just above it in 

THE MOON AT SIX DAYS our picture, diameter 57 

Image Inverted, as in Astronomical Telescope; see Key-Map oppostte miles. Above this is Stibo- 

rius, No. 34, smaller but deeper; and higher still is the group 35, 36, 37,—Pitiscus, Hommel, 
and Vlacq. I follow Webb’s (Beer and Maedler) map here rather than Elger, as it seems 
more clearly related to the photograph. The whole region is much broken, but the group 
can usually be identified by Hommel, with the two smaller ring-plains which it includes. 

In noting the height of the lunar formations it is well to bear in mind the fact that their 
relative altitude is far greater than the actual measurements can indicate. The heights of 
some of our own mountains are, Mont Blanc, 15,775 feet; Mt. McKinley, Alaska, 20,464 
feet; Mt. Everest in India, 29,000; Mt. Etna in Sicily, 10,865. The mountains of the 
moon are lofty even as compared with such standards; *1t it should be borne in mind that 
as the moon is a much smaller globe than our earth, its diameter being only one-fourth as 
great, the relative altitudes on the moon—as compared with its total sphere—should really 
be multiplied by four in making terrestrial comparisons. 





76 HH Beginner’s StareBook 


Note, here, that many objects shown when the moon was six days old are now 
obscured by the more direct lighting from the Sun. In our preceding map, Theophilus, 
Cyrillus, and Catharina—30, 31, 32—were conspicuous; they are now hardly visible. They 
must not be confused with another triple formation, equally striking,—62, 63, 64. These 
are Ptolemy, Alphonsus, and 
Arzachel. The first is the 
most perfect example on the 
moon of the walled plain, its 
diameter being 115 miles 
and its area gooo square 
miles. The second includes 
a bright central peak; the 
third is smaller than the 
second in diameter — only 
66 miles as compared with 
83—but the surrounding 
ramparts are higher, rising 
at one point to 13,000 feet. 
Alpetragius and Herschel, 
65 and 66, are smaller, but 
because of their great rela- 
tive depth they are strik- 
ingly interesting; the walls 
having an elevation of 
13,000 and 10,000 feet re- 
Spectively saslneDit, £07,016 
of interest because of the 
deep crater at its N. E. 
edge. Of the triangular 
group 68; —60,. 70— Pita- 
tus, Wurzelbauer, Gauri- 
cus—the first is of greatest 


interest, because of the . 
breach in its great wall KEY-MAP TO MOON, AT NINE AND THREE-QUARTER DAYS 





See accompanying text, with illustration opposite 


in the direction of the Sea 
of Clouds (N). Of Tycho, 50, we have spoken elsewhere, pp. 71 and 78; the rays are 
not here conspicuous but it may be best studied in the moon of the ninth and tenth days. 
Nos. 71, 72, are Wilhelm I. and Longomontanus, the latter a superb walled plain 90 miles 
in diameter, the highest peak upon its ramparts rising 13,314 feet. Clavius, No. 76, is 
regarded by many as the most variedly beautiful of all the lunar formations. Including 
an area of over 15,000 square miles, the peaks upon its walls rise at two points to at least 
15,000 and 17,000 feet, and upon its great floor are at least five clearly defined craters. 
Nos. 74, 75, are Gruenberger and Moretus, not well placed for observation, and less inter- 
esting than the objects just noted; diameters 40 and 78 miles respectively. Within the 
Sea of Showers, F, we find the ring-plains—77, 78, 79, 80. The first of these, Timocharis, 
though only 23 miles in diameter, is the centre of one of the smaller ray systems; its floor 
lies some 3000 feet lower than the level of the ‘‘sea.’”” Archimedes, 78, is a far finer spec- 
tacle though its depth below the level of the sea is not so great. Its great walls, however, 


The ADoon in the Telescope a7 


rise to a height of 4000 feet above its floor. Aristillus, 79, and Autolycus, 80, are ring- 
plains 34 and 23 miles in diameter, respectively,—the former having a broken and varied 
border and a fine central mountain. These objects, beginning with Archimedes, No. 78, 
are again illustrated on a far larger scale on p. 79. The reader will there find a clearer 
view also of such mountain 
ranges as the Apennines, 57; 
the Caucasus, 59; the Alps, 
60; as well asa closer view of 
Plato, 56, and other objects 
designated in the Key-Maps 
on pp. 76 and 74. 

Southward—or above 
the great Copernicus, 5I— 
lies Rheinhold, 81; and 
farther still to the south- 
ward lies Bullialdus, 82,— 
both formations being now 
almost at the verge of the 
terminator. The former, 
8I, is 31 miles in diameter, 
its walls rising 8000 and 
gooo feet; the inner slope 
showing a clearly marked 
terrace. Bullialdus is even 
more impressive. Its di- 
ameter of 38 miles is not 
remarkable, but its fine 
central mountain, 3000 feet 
in height, the depth of its 
interior level, 4000 feet 
below the ‘‘sea”’ in which 
it lies, and its enclosing 
walls which reach an eleva- 

THE MOON, AT NINE AND THREE-QUARTER DAYS tion of 4000 feet, make it 

Image Inverted, as in Astronomical Telescope; see Key-Map op posite e finely consistent object 

of its class. Equally interesting is Eratosthenes, 58, at the termination of the range of 

mountains called the Apennines, 57. It is 38 miles in diameter, one of its peaks rising 16,000 

feet. Manilius, 61, and Menelaus, 39, have similar names; but the latter, while slightly 

the smaller—diameter, 20 miles—has a finely marked central hill and lies directly on the 
Sea of Serenity, E. See, also, the enlarged photograph on p. 79. 

Just below Copernicus lie the Carpathian Mountains. Copernicus itself, No. 51, is 
the finest of the lunar formations. Its diameter is 56 miles and its massive walls are crowned 
by a number of superb peaks, one of which rises over 11,000 feet above the interior floor. 
On the floor itself near the centre are four or five interior mountains, though these are not 
all easily seen in a small instrument. Tycho, No. 50, is here shown under a very different 
illumination from that presented on p. 70. ‘‘It is,’ says Webb, ‘‘a most perfect 
specimen of the lunar volcano, roughly figured by Galileo in the earliest telescopic represent- 
ations. Its diameter is 54 miles, its depth 17,000 feet or nearly three miles, so that the 








78 AH Beginner's Star-Book 


summit of our Mont Blanc would drop beneath the ring. Its vicinity is thronged with 
hillocks and small craters, so that for a long distance not the smallest level spot can be 
found; further off, the craters increase, till the whole surface of the region resembles a 
colossal honey-comb.”* From the region near Tycho radiates that system of light-rays 





OCCULTATION OF A STAR BY THE MOON 


Aldebaran, at reader's left, just before being occulted or eclipsed by dark limb of Moon; at centre, emerging; at right, shortly after 
emergence. Photograph from the Yerkes Observatory. For greater clearness, the star’s image has been 
slightly enlarged in engraving 


or light-streaks which seems to dominate the scene at the time of full-moon; see p. 71. 
Similar systems, though smaller, seem to come from both Copernicus and Kepler under 
certain phases of illumination, as well as from a number of other points, but the radiations 
from the vicinity of Tycho are the most pronounced in character and the longest in range. 
No one has solved the problem of their nature or origin. The recent theory of Fauth that 
the moon while without water or air is encased in an icy covering, and that the light streaks 
on its surface are due to glacial conditions subjected to direct illumination, has much to 
commend it. 

“There are,” says Noble, in his Hours With a Three-tnch Telescope, ‘‘few more 
curious, instructive, nay even startling sights in the heavens than the occultation of a 
fixed star, or more rarely of a planet, by the moon. When this occurs at the dark limb of 
our satellite, its suddenness is such as not infrequently to extort an exclamation from the 
observer who witnesses it for the first time. . . . In describing her monthly path over the 
celestial vault, it is quite obvious that the moon must pass between us and such stars as lie 
in her course; the stars being—for our present purpose—at an infinite distance, while she is 
only some 239,000 miles from us. . . . Travelling thus, as I have said, from west to east, 
her eastern limb is, of course, the leading one, or that which covers, hides, or occults objects 
lying in her path. From new moon to full moon this limb is unilluminated, and the effect 
of the extremely sudden extinction of a star when the dark limb hides it is, as I began by 
saying, of an absolutely startling character. ‘In a moment, in the twinkling of an eye,’ 
the star which shone as a brilliant point in the sky is blotted out; and its place seemingly 
knows it no more, until it reappears from behind the opposite or illuminated edge of the 


* Celestial Objects for Common Telescopes; by the Rev. T. W. Webb, M.A., F.R.A.S., V Ed., I, p. 121. See also 
The Moon, by Thomas Gwyn Elger, F.R.A.S.; and The Moon in Modern Astronomy, by Philip Fauth, with Introd. 
by J. Ellard Gore, F.R.A.S. To the first two authors, whose volumes are more fully noticed on p. 145, the author 
is especially indebted. 


WESECIOUSECESe La eon COMOO NCO, eTe 2an29, eda 255 elles 


’ 


bp. 76, 74 


Yerkes Observator 
Maps, 


in Key- 


1) 
c 
Ww 
= 
° 
= 
w 
ra 
° 
ed 
rm) 
wo 
a 
z 
< 
> 
EMS 
z 
WW 
[ig 
Ww 
1) 
aL 
° 
< 
ny) 
1) 
u 
° 
z 
° 
oO 
Ww 
c 


THE MOON; 


From enlarged photograph taken with the 40-inch Telescope 











80 El Beginner’s Star-Book 


moon. After full moon, of course, the eastern limb is illuminated, so that the disappearance 
takes place at the bright edge, and the star on its reappearance starts instantaneously from 
behind the dark limb.”’ The more interesting occultations are fully predicted and enumera- 
ted for English readers in Whitaker’s Almanac, and in the Companion to the Observatory; 
and for the United States in the American Ephemeris,—see Note on p. 82. The beginner 
will naturally be interested only in the occultation of the planets or the brighter stars. 
Our illustration shows Aldebaran just before being occulted or hidden by the dark edge 
of the moon’s disk,—then at brief intervals after its reappearance on the moon’s bright side. 


THE PLANETS 


The word planet comes from the Greek word meaning ‘‘wanderer,’’ for the planets— 
unlike the stars proper—have an obvious motion of their own. They belong, like the 
Earth, to “the family of the Sun,’’ moving round the Sun in orbits that are almost circular 
in form. They are distinguished from the ‘‘fixed”’ stars not 
only by their obvious motion but by their relative nearness 
also, see p. 9. 

We read, now and then, that a planet is “in”’ a certain 
constellation,—that Jupiter, for example, is in Scorpio or that 
saturn isin Taurus. This is, of course, a mere convention 
of speech, based upon the apparent place of the planet among 
the stars. The ‘‘fixed”’ stars of the constellations are incon- 
ceivably far away; but as the planets revolve in-their orbits 
they have the stars as their background; and if—as we view 
the heavens from the earth—we find Saturn moving in be- 
tween us and Taurus, with the stars of Taurus as the back- 
ground of the planet, we say that Saturn is “in” Taurus, for 
the planet seems to be among its stars. 

The planets follow a general track or path, and all follow 
the same apparent path through the stars. No one ever saw 
a planet near the Great Dipper, or in Orion, or in Hercules 
or Canis Major. Their path lies in close proximity to a line 
called the ‘‘ecliptic’’; and this same course is followed by 
them all as well as by the Sun and the moon. They keep to 
this path not rigidly, however, but with slight variations to 
one side or the other; and this general track is called the 
Zodiac. The star-groups or constellations which form the 
fixed background of the Zodiac are therefore called the 
zodiacal constellations. The ecliptic, which is itself the path 

SATURN, 1900 of the Sun, will be found clearly indicated on the larger of 

HRC T SAA OLEAN) the two maps at the close of this volume. Each planet is 
always somewhere in the Zodiac and is said to be ‘‘in” the constellation lying at the 
background of this position. The Zodiac or track of the planets lies through the following 
constellations:—Aries, the Ram; Taurus, the Bull; Gemini, the Twins; Cancer, the Crab; 
Leo, the Lion; Virgo, the Virgin; Libra, the Scales or Balances; Scorpius, the Scorpion; 


‘ 





Che Planets 81 


Sagittarius, the Archer; Capricornus, the Sea-Goat; Aquarius, the Water-Bearer; Pisces 
the Fishes.* The Zodiac extends 8° on each side of the ecliptic. 

The Greeks reckoned seven as the number of the “‘planets,’”’ but they included both 
the Sun and the moon in the list. We do not, of course, include the Sun and moon, but 
the number is for us seven also,—for we have added to the list in 
modern times two planets that the Greeks did not know, Uranus 
and Neptune. The names of the planets, in the order of their 
distance outward from the Sun, are here printed, with their con- 
ventional symbols:—8 Mercury; 2 Venus; © Earth; & Mars; 
2} Jupiter; k Saturn; 6 or H Uranus; Y Neptune. The largest 
planet is Jupiter—with diameter nearly eleven times that of 
the earth; the smallest is Mercury, its diameter a little over } 
that of the earth. Between Mars and Jupiter are a large num- 
ber of small planetary bodies called Asteroids, many of them 
only twenty or thirty miles in diameter. These are probably 
the disunited elements of a planet of importance,—whether ar- 
rested in development, or once perfect and now destroyed, no 
one can say. 

On the subject of each of the planets a whole volume might 
be written. In this book there is space only for a few words to 
the beginner concerning their observation with the telescope. 
As they move about among the stars it becomes important, first 
of all, to be able to identify them. Two aids should be pos- 
sessed by every amateur observer who wishes to know their 
positions with accuracy,—these are (1) a good almanac for the 
current year, and (2) the national Ephemeris of the country in 
which he wishes to observe. See footnote on next page. 

The beginner is quite likely, just at first, to confuse the 
brighter planets with the brighter of the fixed stars. Such errors 
need not surprise or discourage, for they will soon find correction. 
One of the best of correctives is a fair knowledge of the constella- 
tions. As the stars which keep their places come to be known, 
it becomes a simpler matter to identify the objects which show 
obvious changes of position. The planets, like the moon, do not 
move about at random in the sky, but keep their track through the 
Zodiac, as stated on the preceding page. In distinguishing them, MARS 
a telescope will also assist. The stars show an increase of bright- From the Yerkes Observatory 
ness in the telescope but no increase in size. The planets, however, show a perceptible 
disk or surface image. Saturn, moreover, is quickly indicated by its ring, Jupiter by his 
four larger moons. It is often said that, to the unaided eye, the stars may be distinguished 
from the planets by their twink'ing. It is true that, as a rule, the light of the planets is 


) 





* The beginner need not pause over this footnote concerning the “‘szgns”’ of the Zodiac. These are fixed divisions 
of the ecliptic, each occupying 30° along the circle. These divisions or spaces or ‘‘mansions”’ of the Sun in its path 
were once coincident with the constellations whose names they bear, but they are not so any longer, each ‘‘sign”’ 
(or space of 30°) now corresponding to the constellation preceding it,—the sign of Aquarius really applying, approxi- 
mately, to the region along the ecliptic occupied by the stars of Capricornus; the szgn of Capricornus applying, 
approximately, to the region of Sagittarius, etc., and finally the sigm of Aries falling in Pisces. The conventional 
symbols of the ‘‘signs” are as follows:—Aries ©; Taurus 8; Gemini; Cancer 3; Leo 2; Virgomy; Libra +; 
Scorpio M; Sagittarius ¢ ; Capricornus 45; Aquarius 4”; Pisces *. In almanacs, etc., these symbols apply to the 
“signs, ’’ not to the constellations themselves. 


6 


82 H Beginner’s StareBook 


far steadier; but there are times when Venus and even Jupiter will seem to twinkle most 
amazingly, and there are other times—the atmospheric conditions being good—when the 
light of the stars will be calm and undisturbed. For “twinkling” is caused primarily by 
the unsteadiness of the air. 

In the Tables here printed, the approximate 
position of the brighter planets is shown month 
by month for an extended period. These references 
are not to the conventional ‘‘signs’’ but to the 
constellations themselves. Such tables cannot be 
absolutely accurate, but they will well serve as a 
rough practical guide; and, if the planet be not 
precisely within the constellation indicated, it will 
be found sufficiently near to make its identification 
possible. No tables for Mercury, Uranus, and Nep- 
tune are presented, the first being so near the Sun 
that the stars of the constellations in which it ap- 
pears are largely obscured at the time by the Sun’s 
light. Uranus and Neptune, on the other hand, 
are at such great distances from the Sun (1,781,- 
000,000 and 2,791,000,000 miles respectively) that 
they are too faint in a small instrument to be 
interesting telescopic objects. Their positions in 
R. A. and D. may be found from the national 
Ephemeris,* if desired. Uranus shines as a star of 
about the 6th magnitude; Neptune as a star of 
magnitude 8, though each presents a slight disk, and 
careful watching will indicate its slow motion among 

Photographed at the Lowell Observatory, Flagstag, the stars. 

Arizona The planetary Tables here printed may be used 
as follows in connection with the Time Schedule of the Key-Maps on p. 35. (1) We 
may wish to know whether or not a particular planet (Venus, Mars, Jupiter, or Saturn) 
is to be seen in the evening sky on a given date. First, find in these Tables the con- 
stellation in which at that date the planet is likely to be found. Then from p. 35 find 
the pages on which the Key-Maps are given for the evening sky on the date in question. 
If the constellation is not shown in these maps, the planet is not visible in the evening 
sky. If the constellation appears upon the maps, the planet in question will be found 
therein. (2) We may wish to know which of these planets are in the sky on a particular 
evening. First, look for the date—year and month—in these Tables. Note the constella- 





JUPITER, 1910 


* For the United States, the observer should write to ‘‘The Superintendent of Documents,’’ Washington, D. C., 
enclosing $1.00 and asking for the American Ephemeris and Nautical Almanac for the year desired. The volume 
may always be had a year in advance. It will contain much that the beginner will not want but it will also contain 
the position of the moon and planets by Right Ascension and Declination for each day; the predictions of all occulta- 
tions by the moon for the year, see p. 78; the eclipses of the year; and the phenomena of the satellites of Jupiter and 
Saturn. In Canada, the same data are to be found in the Annual of the Canadian branch of the Royal Astronomical 
Society; in Great Britain in the Nautical Almanac as well as in such publications as Whitaker’s Almanac and the 
Companion to the Observatory. Clear and simple tables showing the hours of rising and setting of the planets, the 
phases of Venus, and much other useful information may be had, in the United States, in such annual almanacs as 
those published by the New York Tribune and the Brooklyn Eagle. The Tribune Almanac is published, 25c., at the 
opening of each year. An even simpler volume, Ioc., is the Old Farmer's Almanack, published by William Ware & 
Co., Boston, Mass. For its weather predictions I would not be responsible. 


The Planets 83 


tions in which the planets occur. Then find the evening sky for the date in question by 
reference to p. 35. For example, if our approximate time be the early evening of March, 
1912, we find from the Tables here that Mars is in Taurus, Saturn in Aries, Jupiter in 
Scorpio, and Venus near the boundary between Capricornus and Aquarius. The Time 
Schedule of the stars, p. 35, refers us to 
pp. 43, 45, for the skies of the early even- 
ing in March. As Scorpio, Capricornus, 
and Aquarius are not in the skies shown, 
we know that Jupiter and Venus are not 
visible. As Taurus and Aries are shown, 
well over to the west in our Key-Map of 
the sky, see p. 45, we know that Saturn and 
Mars are visible and are there before us. 
As the field covered by our map is rich in 
brilliant stars, a little care must be given to 
distinguishing the planets from the “‘fixed”’ 
stars. But from the suggestions given on 
p. 81, and from the general appearance of 
the planets as indicated in the following 
paragraph, this should not prove very 
difficult. (3) We may see a bright ob- 
ject in the sky, not conforming to the lines 
of the constellation figures, and may wonder 
what planet it is. On July Ist, 1913, at 
9g o'clock P.M., we may see a bright object 
toward the southeast, not conforming to 
the outline of the constellation as shown SATURN, 1910 

in the Key-Map designated, p. 35, for that Photographed at the Lowell Observatory, Flagstaff, Arizona 

date. It seems too bright for a fixed star and yet we are uncertain as to its identity. 
Noting from the proper Key-Map that the object is ‘‘in’’ Sagittarius, we search here in 
our planetary Tables for the date in question and find that Sagittarius is given, July, 1913, 
as the place of Jupiter.. Jupiter, therefore, is the unknown object. 

Mars can often be distinguished by its reddish glow; Saturn by its steady yellow light; 
Jupiter by its great size, and the soft white color of its globe. Venus is also large and 
brilliantly white, but it can usually be distinguished from Jupiter by its proximity to the 
Sun. Jupiter may sometimes be seen throughout the night. Venus must usually be seen 
shortly after sunset or before sunrise; it can never be seen at midnight or at any position 
which would involve its being at any great distance from the Sun. 





MeERcurY (8) 


Mercury is even nearer the Sun than Venus; and while at times quite bright, it is so 
constantly lost for us in the excessive light that the mere seeing of it is, for the amateur 
observer, a real achievement. Copernicus is said to have died without ever beholding it. 
But if the observer will note his current almanac for the times of its ‘‘greatest elongation”’ 
it may be seen at such times near ‘‘the place of the Sun”’ low down toward the horizon, 
just before sunrise or just after sunset. Mercury shines about as brightly as a first mag- 
nitude star. An opera-glass or field-glass is often very useful in the search for it. The 


84 


H Beginner’s StareBook 


THE PLACE OF VENUS, MONTH By MONTH, TO 1931 


The abbreviations in this Table are:—Taur = Taurus; Gem =Gemini, including Cancer; Leo V =near boundary 
between Leo and Virgo; Scorp L==near boundary between Scorpio and Libra; Sag=Sagittarius; Cap Aq =near 


boundary between Capricornus and Aquarius. 
ter> M=Mars; S=vaturn. 


constellation in the same month. 






































The small initials at upper left corners of squares are, J =Jupi- 
The use of such initial means that the planet thus symbolized is also in that 






















































































































































































Year Jan Feb Mar Apr May | June July Aug Sept Oct Nov Dec 
IQII Cap | Aquar} Pisc Taur | Taur | Cancer| Leo Leo | LeoV | LeoV |} Virgo | Virgo 
J M M 
1912 | Scorp Sag /Cap Aq] Pisc Aries | Taur | Gem Leo Virgo |Scorp L} Sag Cap 
M MS 
LOTS wa AC ate ELS Aries | Aries | Aries | Aries | Taur | Gem | Cancer| Leo V | Virgo | Scorp 
iS) S M M 
I9I4 Sag /Cap Aq| Pisc Taur | Taur | Gem Leo Virgo |Scorp L\Scorp L\Scorp LiScorp L 
M M MS MS 
1915 Sag Sag |Cap Aq| Pisc ANTICS eae battcin iedue ttt Leo Leo V | Virgo Sag Sag 
s S S S S : 
1916 |Cap Aq| Pisc Laur.) Taurean elaurcn © Canre Gem Leo | Leo V | Virgo |Scorp L 
M IM M JM s 
IQI7 Sag |Cap Aq] Pisc Aries | Taur Gem Leo Leo V | Virgo Sag Sag Sag 
SS) M 
1918 Sag Sag |Cap Aq] Pisc Aries | Taur | Taur | Gem Leo Virgo |Scorp L) Sag 
'M M M s M M 
1919 |Cap Aq| Pisc Aries)! elaury ylaur Leo Leo V | Leo V | Leo V | Leo V | Leo V | Virgo 
S M 
1920 Sag Sag |Cap Aq] Pisc Taur | Taur | Gem Leo Virgo |Scorp L} Sag Sag 
M M M M M MS Af 
1921 Pisc Aries | Aries | Taur | Aries’ | Taur  Taur | Gem Leo | Leo V | Virgo |Scorp L 
J J) J iM 
1922 Sag™ iCap Aq! Pisce Taur | Taur | Gem Leo Virgo |Scorp L|Scorp L\Scorp L/Scorp L 
M M Sie oh J 
1923 Sag Sag |Cap Aq| Pisc Aries | Taur | Taur Leo Leo V | Virgo Sag Sag 
| S 
1924 |Cap Aq| Pisc Ateeee | “Ieee || Weyewe || “Wekene |) “Menewe Gem Leo Leo V | Virgo |Scorp L 
i! ; M M Sar if J A) 
| 1925 Sag |Cap Aq| Pisc Aries | Taur | Gem Leo Leo V | Virgo Sag Sag Sag 
M J S 
1926 Sag Sag |Cap Aq] Pisc Aries | Taur | Taur | Gem Leo Virgo |Scorp L| Sag 
a. J M M M : 
1927 |Cap Aq| Pisce Aries Mauree lav Leo Leo V | Leo V | Leo V | Leo V | Leo V | Virgo 
MS MS S S) 
1928 Sag Sag |Cap Aq| Pisc ‘tanie || sheyotr Gem Leo Virgo |Scorp L| Sag Sag 
J J 
1929 Pisce Aries | Aries | Taur Aries | Taur ARERR Leo Leo V 
MS M J 
1930 Sag |Cap Aq] Pisc Taur | Taur Gem Scorp L/Scorp L 






























































































Facts about Venus :— The diameter of Venus is 7700 miles; the Earth’s 7918; the two planets being almost the 


same size. Venus is 67,200,000 miles distant from the Sun, revolving about the Sun in 224.7 days,—this being the 
year of Venus. The period of the rotation of Venus on its axis is now thought to be the same as the period of its 


year,—though this is not altogether certain. The planet moves in its orbit at a velocity of 22 miles a second and for 


every 100 units of sunlight that fall on Venus 76 are reflected back into space. 


12 times the brightness of Sirius; and has 60 times the brightness of Arcturus. 


At greatest brilliance Venus has 


The Planets 85 


planet is best seen in the morning at such western elongations as occur in September and 
October; it is best seen in the evening at such eastern elongations as occur in March and 
April. For the exposition of such terms the reader may refer to any text-book on Astron- 
omy ; see p. 144; but notes and dates of the elongations will be found in any ordinary current 
almanac. As a telescopic object, Mercury shows almost no detail in a small instrument, 
but it is always of interest to watch for its ‘‘phases.’’ It often assumes—as does Venus— 
the appearance of a brilliant crescent moon. 

These briefly stated facts about Mercury may be of interest:—The diameter is 3030 
miles, that of our Earth being 7918 miles. The mean distance of Mercury from the Sun 
is 36,000,000 miles, but the eccentricity of the orbit is so great that the distance varies 
between 28,500,000 and 43,500,000 miles. It revolves round the Sun once in about 88 
days (this is, therefore, the year of Mercury). The planet moves in its orbit at a velocity 
of from 23 to 36 miles a second, always turning the same side toward the Sun. For every 
1oo units of sunlight that fall upon its surface, 14 units are reflected back into space. 
For these and other data concerning the planets I wish to express my special obligations 
to the Astronomie (IV German Edition), of Newcomb-Engelmann; The Family of the Sun, 
by Holden; A Manual of Astronomy, by Young. ‘These are noted more specifically in the 
List of Books, at the close of this volume. 


VENUS (¢) 


Venus is so brilliant an object to the eye that the beginner is tempted to expect much 
from it as a telescopic object. These expectations, however, are never quite fulfilled: 
the planet is so very brilliant and presents so little detail that it is impossible for the tele- 
scope, even though it be a large and perfect instrument, to present a clearly defined image 
of its sphere. It varies much in apparent size and form, as is well 
indicated in our smal! illustration, Fig. 12. It is extremely beauti- 
ful, even in a good field-glass, when it puts on the crescent phase. 
This it does for some weeks before and after “inferior conjunction.”’ 
For the dates of such conjunctions, see any current almanac. Within 


o>) 


this period Venus is at its greatest brilliancy, often being visible by "Fig. 12. Venus 
daylight and casting a distinct shadow of its own. Just at inferior Changes in Apparent Size and 





conjunction, and for a few days before and after, the planet EAE oe Aaa 


is hidden within the light of the Sun. When midway between greatest elongation and 
inferior conjunction, its apparent diameter is so great that in the telescope, even with a 
magnifying power of 45, it assumes the size of the four-day moon, as viewed by the unaided 
eyes. Venus will not be a satisfactory object for observation during 1912. But she will 
be ‘‘at her best’’ as follows:— Before sunrise, November, I911; June, 1913; January, 1915; 
September, 1916; April, 1918; November, 1919; July, 1921; February, 1923, etc. And 
after sunset, February, 1913; September, 1914; April, 1916; November, 1917; July, 1919; 
February, 1921; September, 1922; April, 1924, etc. 


Mars (<) 


As Mars is farther from the Sun than our Earth, it can never exhibit a crescent phase, 
as do Mercury and Venus. But, while its orbit is almost circular, its apparent movements 
are so peculiar, when viewed in relation to the stars through which it moves, that the 
beginner will find it interesting to follow and plot its course. Make a diagram of the stars, 


86 H Beginner’s StareBook 


THE PLACE OF Mars, MonTH By MONTH, TO 1931 


The abbreviations in this Table are:—Taur = Taurus; Gem =Gemini, including Cancer; Leo V =near boundary 
between Leo and Virgo; Scorp L=near boundary between Scorpio and Libra; Sag=Sagittarius; Cap Aq =near 
boundary between Capricornus and Aquarius. The small initials at upper left corners of squares are, J =Jupi- 
ter; S=Saturn; V=Venus. The use of such initial means that the planet thus symbolized is also in that 
constellation in the same month. 


Year Jan Feb Mar Apr May | June July Aug Sept Oct Nov Dec 














S S) 
IQII Scorp Sag Cap |Cap Aq} Aquar| Pisc Aries | Aries | Taur | Taur | (Dagar 








7 








Vv 
topo. j/ “excite || eye | Abner |) (Ersen Gem |Cancer| Leo | Leo V | Virgo | Virgo | Libra |Scorp L 








J J Vv SV Ss 
I9I3 Sag Sag |Cap Aq| Aquar | Pisc Aries 1) Patir ) | "Laur Gens Gem Gem | Gem 
Ne V 
IQI4 Gem Gem | Gem | Gem Leo Leo | Leo V | Virgo | Virgo |Scorp L} Sag ‘Sag 








J V SV SV 
1915 Sap |Cap Adis Pisce Aries | Aries | Taur | *Daur Gem Gem Leo Leo Leo V 




















1916 | Leo V Leo Leo Leo Leo Leo V | Leo V | Virgo |Scorp LiScorp L} Sag Sag 



























































Vv Vato AV. JV J J S 

1917 |Cap.Aq|Cap Aq| Pisc Aries | Vaur | Taur |) 2latire} Gem Leo Leo | Leo V | Leo V 

Vv 

1918 | Virgo | Virgo | LeoV | Leo V | Leo V | LeoV | Virgo | Virgo |Scorp L} Sag Sag Sag 
Vv Vv aa? Vv Js Js Vv Vv 

1919 |Cap Aq} Pisc Pisce Aries | Taur | Taur | Taur | Gem Leo Leo Leo V | Virgo 

Vv 

1920 | Virgo | Virgo /Scorp L] Virgo | Virgo | Virgo | Virgo |Scorp L|Scorp L| Sag Sag [Cap Aq 
V |V V V V SV S) ij 

1921 Pisc Pisc Aries’ | “Taur’ || Taur | Laur) Geni Leo Leo Leo V | Leo V | Virgo 








1922 |Scorp L\Scorp L} Sag Sag | Sag Sag Sag Sag Sag Sag |Cap Aq|Cap Aq 















































Vv V Ss S 
1923 Pisce Aries Aries | Taur | Taur Gem Gem Leo Leo V | Leo V | Virgo | Virgo 
J J J 
1924 |Scorp L} Sag Sag Sag |Cap Aq/Cap Aqg/Cap Aq/Cap Aq|Cap Aq|Cap Aq/Cap Aq] Pisc 
V V Ss 
1925 Pisc Aries | Taur | Taur | Taur | Gem | Gem Leo | Leo V |! LeoV | Virgo |Scorp L 
Ss V jj J é 
1926 |Scorp L} Sag Sag |Cap Aq/!Cap Aq| Pisc Aries | Aries | Aries | Aries, | Aries | Aries 
V V V 4 S 
1927 Aries | Taur darece || Aayeer Gem Gem Leo Leo V | Leo V | Virgo |Scorp L|Scorp L 





SV SV S : he is 
1928 Sag Sag Sag |Cap Aq] Pisc Aries | Aries | Taur | Taur | Taur | “Tauriieeteoe 








S 
1929 Taur | Taur | Taur | Gem Gem Leo | Leo V | Leo V | Virgo | Virgo |Scorp L| Sag 


Sv V J J 
1930 Sag Sag |Cap Aq} Pisc Aries) lauryl daur je Laur) Gem Gem Leo Leo 















































Facts about Mars : — The diameter of Mars is 4,230 miles. The planet’s bulk (size) is xo that of the Earth. Mars 
turns on its axis in 24 hours, 37 minutes, 22.67 seconds,—this being the day of Mars. The planet revolves about the 
Sun—at a mean distance of 141,500,000 miles—in 686.9 days,— this being the year of Mars. ‘The velocity of its 
motion in its orbit is 15 miles per second. For every 100 units of sunlight that fall on its surface 22 units are reflected 
back into space. Mars, the planet of War, has two moons, Deimos and Phobos (Fear and Flight). These are so 
small, however, that they may be seen only by the trained eye through a very large telescope under perfect atmospheric 
conditions. Their diameters are only about 35 and 10 miles respectively; some observations give only 7 and 5. The 
inner satellite, Phobos, has a period of only 7 hours, 39 minutes, less than 3 of the planet’s day. As viewed from the 
planet’s surface, it rises in the west and sets in the east, making about 3 complete revolutions to the day. If there 
be inhabitants on Mars, Phobos must serve as a very fair time-piece. 


The Planets 87 


and then from week to week draw a line through them corresponding to the movement 
of the planet. While some of the more conspicuous markings of the surface are visible in a 
small telescope the so-called ‘‘canals’’ cannot be seen except in large instruments under 
favorable conditions. Mars is nevertheless a beautiful telescopic object even for the 





MARS, 1909 
Drawing by Dr. Percival Lowell, Flagstaff, Arizona 


beginner,—its clearly defined image and its ruddy light giving a peculiar fascination to 
such faint details as do appear. Among these are the ‘‘hour-glass’’ marking, so named 
from its peculiar shape, and the cap of polar snow—though the question as to whether its 
composition is really that of frozen water is not decided. No object in our night skies, 
except the moon and one of the small asteroids, comes so near the Earth as does Mars 
at the time of a favorable “‘opposition.”’ The planet then shows in a telescope, with a 
power of 75, a disk as large as that presented by the moon to the unaided eye. At such 
times its magnitude on a stellar scale is —2.8, the planet then having three times the 
brightness of Sirius. 

Problems as to the habitability of Mars lie wholly outside the limits of this volume. 
I may say, however, that the question as to “‘life in other worlds”’ is not dependent upon 
the solution of the problems which arise from the planet Mars. We know that all the 
millions of the fixed stars are suns, many of them greater than our own. We cannot prove 
that these are accompanied by planets—as is our Sun—for no instrument we could devise 
could ever reveal their presence—the suns themselves being at such great distances from 
us. But most astronomers are agreed that the existence of such planetary systems is 
altogether probable. 

Nor can we prove that on any one of these planets there certainly exists what we call 
“life.”’ We can only remember that life upon our own planet has persisted and developed 
under conditions of great difficulty; and that persistent phenomena are not likely to be 
isolated factors in the universe. We find no isolated laws—gravitation is apparently as 
active at the very verge of “‘the darkness beyond the stars” as it is upon our Earth. 
The principles of mechanical action and reaction hold there as here. The spectroscope 
no sooner reveals ‘‘new”’ elements in the chemistry of the Sun and in the nebule of the 
sky, than we begin to discover the same elements in the composition of our own minerals. 
Astronomy has revealed the vastness of the universe,—but it is now revealing the unity 
of the universe with evidence as clear in its significance and as cumulative in its force. 


88 H Beginner’s Star-Book 


THE PLACE OF JUPITER, MONTH By MONTH, TO 1931 


The abbreviations in this Table are:—Taur = Taurus; Gem =Gemini, including Cancer; Leo V =near boundary 
between Leo and Virgo; Scorp L=near boundary between Scorpio and Libra; Sag =Sagittarius; Cap Aq =near 
boundary between Capricornus and Aquarius. The small initials at upper left corners of squares are, M =Mars; 
S=Saturn; V=Venus. The use of such initial means that the planet thus symbolized is also in that 
constellation in the same month. 





fi 
Year Jan Feb 








TF 
Mar Apr May June July Aug Sept Oct Nov Dec 











| IQri Libra | Libra | Libra | Libra | Libra | Virgo | Virgo | Libra | Libra | Libra | Libra )))Sceorp 








V 
1912 | Scorp | Scorp | Scorp | Scorp | Scorp | Scorp | Scorp | Scorp | Scorp | Scorp | Scorp | Sag 


M |M 
1913 Sag | Sag | Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag 




















Vv 
1914 |Cap AqCap Aq|\Cap Aq|Cap Aqi/Cap Aq|Cap Aq|Cap Aq|Cap Aq|Cap Aq/Cap Aq|Cap Aq|Cap Aq 








M 
1915 |Cap Aq| Pisc Pisc Pisc Pisc Pisce Pisc Pisce Pisc Pisc Pisc Pisce 



































Vv 
1916 Pise Pisc Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries 
: VM M M | 

1917 | Aries | Aries | Aries | Taur | Taur >| Laur | .Taur | Daur |) Laur |) Dar ela ees 

; | ce a NW V 

1918-| Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taur |) Laurl) = ieaqqeeeee 
| | S s ISM  |SM S s 

1919 Gem Gem Gem Gem Gem Gem Leo Leo Leo Leo Leo Leo 
iS S S S S ‘Ss S |S S SS) Ss) 

1920 Leo Leo Leo Leo Leo Leo | Leo | Leo V | LeoV | Leo V | Leo V>) Cea 





| 


iS IS 
1921 | Leo V | Leo V 


S S Vv M 
Leo V | Leo V | Virgo | Virgo | Virgo | Virgo 





‘Ss S S S 
Leo V | Leo V | Leo V | Leo V 








V V V Vv 
1922 | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo |Scorp L\Scorp L|/Scorp L 





























Vv V 
1923 |Scorp L/Scorp L/Scorp L/Scorp L/Scorp L/Scorp L/Scorp L Scorp L|Scorp L\Scorp L} Sag Sag 
*. J) Eee Oh | en a a a 
1924 Sag Sag Sag Sag | Sag Sag Sag | Sag Sag Sag Sag Sag 
| |V | Vv Vv Vv 


| 1925 | Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag 











V M M 
1926 Cap Aq Cap Aq(Cap AqjCap Aq|Cap Aq/Cap Aq|Cap Aq|Cap Aq|Cap Aq|Cap Aq/Cap Aq/Cap Aq 








V \V 
1927 |Cap Aq| Pisc Rise Rise Pise Pisc Pisce Rice Pisce Ierise Pisce Pisc 
; M M: JER eee 



































1928 Pisc Rise Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries 
AV an BY Vv Vv | 
| 1929 Aries |) Aries | Aries | Taur | Taur | Taur.| Taur | Taur | Taur | Taur |) (acces 
V Vv Vv M M 



































ieee) || Aekenp || “Wake? |) Aensee | “Adenese | Ihexone Gem Gem Gem Gem Gem Gem Gem 





Facts about Jupiter :—In addition to the facts already cited, it is well to remember that although so great in size, 
Jupiter turns on its axis in only 9 hours and 55 minutes (the day of Jupiter). This motion being so rapid and the 
density of the planet being so low, there has taken place an obvious flattening at the poles. Jupiter goes round the 
Sun once in 11.86 years (the year of Jupiter) at a mean distance of 483,300,000 miles; the velocity of the orbital 
motion being 8 miles per second. For every 100 units of sunlight that fall on the planet’s surface, it is estimated that 
62 units are reflected back into space. The planet at its brightest has about twice the brilliancy of Sirius. Jupiter has 
eight moons in all—four being too small for observation with the average telescope. 


Che Planets 89 


That such a phenomenon as “life,” persistent here through such varied and difficult 
conditions, through so long a period and under so many forms, is a unique and isolated 
fact becomes increasingly improbable. The beginner may be warned, however, that such 
suggestions are speculative, and that they lie largely outside the domain of astronomy proper. 


JUPITER (21) 


Jupiter is truly called the giant planet, for it is not only 1,309 times the bulk (size) of 
the Earth, but larger than all the other planets combined. Its weight, however, is only 
about 13 times as great as the same quantity of water, so that its density is much less 
than that of our Earth or our moon. Its chief fascination in the telescope lies in the move- 
ments of its four larger satellites. These can be seen 
even in a 10x field-glass steadily held, and their ob- 
servation in a small telescope may prove a source of 
great interest and pleasure. They are known, in the 
order of their distance from the planet, as I, II, III, 
IV,—their names being Io, Europa, Ganymede and 
Callisto. Allare larger than our own moon, Ganymede 
—the largest and brightest—having a diameter of 
3,600 miles. 

They are not always placed as in our little pic- 
ture, Fig. 13. Sometimes all four are to be observed on one side of the planet; some- 
times we may see three on one side and one on the other. At times, one will pass, 
in its orbit, behind the planet and be lost to view; or it will be lost to view as it 
passes in front of Jupiter, being obscured in the planet’s greater light and casting a 
tiny shadow on the planet’s disk. These movements take place with such rapidity that 
the apparent changes of position may often be detected in a couple of hours. It is 
worth while, therefore, to take two observations of Jupiter on the same evening, if possible, 
one at an early hour and one later. 

The movements of these moons of Jupiter, their aeitthtt, eclipses, etc., are all predicted 
and set forth in the national Ephemeris to which reference has been made in the footnote 
on p.82. A small telescope will also show the flattening of the planet’s globe at the poles 
and the two greater cloud belts. The markings as shown in Fig. 13 are too sharply defined. 
As the size of the telescope is increased, more and more detail, however, can be seen, and 
sometimes a large marking, called ‘“‘the great red spot,’’ can be discerned. As Fowler 
suggests, any detail that can be noted must be important in size, for the diameter of the 
planet is about 86,500 miles. Drawings of the disk of the planet, if carefully made, are 
often of future interest and value. 





Fig. 13. Jupiter 
With his Four Larger Moons 


SATURN (hk) 


This is one of the most beautiful of telescopic objects. The ring formation revolving 
about the planet—a thing unique, so far as our knowledge of the universe extends—may 
be seen in any good telescope that will yield a power of 20 diameters. The beginner, 
however, will usually require an instrument a little larger, with an object-glass of 2 or 
214 inches in aperture, in order to see this formation with any real satisfaction. Every 
increase in the size and quality of the telescope will add new clearness and beauty of 
detail; for Saturn will well bear all the magnifying power consistent with the capacity 
of the eye and the instrument. 


90 fl Beginner’s Star=Book 


THE PLACE OF SATURN, MONTH BY MONTH, TO 1931 


The abbreviations in this Table are:—Taur =Taurus; Gem =Gemini, including Cancer; Leo V =near boundary 
between Leo and Virgo; Scorp L=near boundary between Scorpio and Libra; Sag=Sagittarius; Cap Aq =near 
boundary between Capricornus and Aquarius. The small initials at upper left corners of squares are, J =Jupi- 
ter; M=Mars; V=Venus. The use of such initial means that the planet thus symbolized is also in that 
constellation in the same month. 






































































































































ee a ES! 
Year Jan Feb Mar Apr May | June July Aug Sept Oct Nov Dec 
M M eT 
I9i1 | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries | Aries 
= | eee 
1912 |. Aries | Aries |. Aries | Aries | Taur | Taur | Taur | ‘Taur | Taur | Tauree Vamees 
a MV |M M | 
1913 | Taur | -Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taur ) Daur 
V Vv 
1914 | Taur | Taur | Taur | Taur.| Taur | Taur | Taur | Taur | Taur | Tauri cues 
oun oo ie eon Tees ota ties eet eeu. ae. 
I9I5 Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taur | Taury vance 
WRU ao V V V V vel 2S) ee Ve ae 
1916 | Taur | Taur |-Taur | Taur | Taur | Taur | Gem | Gem | Gem | Gem) =Genimeaem 
Vv <a: M a 
1917 | Gem | Gem | Gem | Gem | Gem | Gem | Gem | Gem | Gem | Gem | Gem | Gem 
a ee | 
1918 Gem | Gem | Gem | Gem | Gem | Gem | Gem Leo | Leo Leo Leo Leo 
| v J J IM |M |5 J 
1919 Leo Leo | Leo Leo Leo Leo Leo Leo Leo Leo Leo Leo 
J i [J J J J J Vv J J J J 
1920 Leo Leo | Leo Leo Leo Leo Leo Leo | Leo V | Leo V |} Leo V |} Leo V 
J J J J J J J J MV _ IM 
1921 | LeoV.| LeoV | Leo V'| LeoV | LeoV | LeoV | Leo V | LeoV | LeoV | LeoV | Leo V} Leo V 
1922 | Leo V | LeoV | LeoV | LeoV | LeoV | LeoV | Leo V | LeoV | LeoV | Virgo | Virgo | Virgo 














V M M 
1923 Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo 

















V 
1924 | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo 





Vv M 
1925 | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo | Virgo |Scorp L|Scorp L 














M V 
1926 Scorp L\Scorp L|Scorp L/Scorp L/Scorp L/Scorp L\Scorp L|Scorp L/Scorp L|Scorp L|Scorp L|Scorp L 








M 
1927 Scorp L\Scorp L\Scorp L/Scorp L|Scorp L/Scorp L|Scorp L\Scorp LScorp L|Scorp L\Scorp L} Sag 
VM VM M Vv v 










































































1928 Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag 
M 
1929 Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag Sag 
VM 
1930 Sag Sag Sag Sag Sag Sag Sag 








Facts about Saturn:—In addition to what has been said, it may be interesting to note that the diameter of Saturn’s 
sphere is about 73,000 miles,—about nine times that of the Earth. Saturn is distant from the Sun 886,000,000 
miles, or about 914 times as far from the Sun asis the Earth. It takes 29.46 of our years for Saturn to go completely 
round the Sun,—this period representing, therefore, the year of Saturn. The planet moves in its orbit at a velocity 
of 6 miles a second; and for every 100 units of sunlight falling on it, about 72 units are reflected back into space. 
Saturn is the most remote from the Sun of the planets known to the ancients. Galileo partly discovered the “‘rings,”’ 
but his largest instrument was too imperfect to exhibit their real structure. They soon turned ‘‘edge on,’’ as in 1907, 
and he died without solving the mystery. That the appearances which baffled Galileo were rings was discovered by 


Huygens, the Dutch astronomer, in 1655. 


Che Planets gI 


The ring formation is seen, with higher powers, to be divided, and to present the 
following conditions. The observer first notes—even in a telescope of 314 or 314 inches 
—that the encircling mass is divided into two bright rings, called by 
astronomers, A and B. They are separated by a dark line called 
PGacsitins) Sore, Ball's: = Division: 
A is the outer ring, its exterior 
diameter being 173,000 miles. Its 
light is of a hue more golden than 
that of the second ring, B. The 
light of B is brighter and more 
silvery. In A there is a further 
line called Encke’s Division; and 
at the inner edge of B there is a 
darker ring, C,—sometimes called 
the ‘‘gauze’’ ring because of its 
shadow -like texture. But this 
phenomenon, as well as Encke’s 
Division, can be seen only in the 
largest telescopes. The rings of 
Saturn are swarms of tiny satel- 
lites, or ‘‘moonlets,’’ each revolv- 
ing in its own orbit. ‘The rings 
are really circular—their appar- 
ently elliptical form being due to 
the angle at which we must view 
them from the Earth. If we were 
directly above Saturn, or directly 
below, we should be able to see ene 
that they are circles. From Photograph by Dr. Percival Lowell, Lowell Observa- 

The constant changing of the eset ea 
relative positions of Saturn and the Earth, as the two planets move in 
their orbits round the Sun, naturally changes the direction from which 
we see the rings. Sometimes our line of sight is such that we view the 
rings ‘“‘edge on” as in 1907. They are then almost invisible. In our 
illustration, Fig. 14, which I here use by courtesy from Prof. David Todd’s 
Fig. 14, Phases from admirable New Astronomy, the “phases” of Saturn are shown through an 

zo07: 10 1936 extended period, till 1936. They are so beautiful in a small telescope under 
even moderate powers that they form an exhaustless source of charm and interest. 

Saturn is accompanied by ten moons, Their names are Japetus, Hyperion, Titan, 
Rhea, Dione, Tethys, Enceladus, Mimas, Phoebe, and Themis. The whole system is 
very great in its extent, Phoebe being at a distance from the planet of 7,860,000 miles. 
Even a 2-i1-ch telescope will usually show Titan, the largest. A 3-inch telescope will 
sometimes show Japetus, next brightest, and—on rare occasions—even a third, Rhea. 
A 4-inch will usually add two others. The apparent motion of the satellites of Saturn 
is so much slower than in the case of the moons of Jupiter, and their relation to the 
planet is so much less obvious, that their interest for the observer is not so great. 
The bulk (size) of the globe is more than 750 times that of the Earth, though it 
possesses a density less than that of water. As this huge mass revolves on its axis 





Saturn 


HALLEY’S COMET, MAY 5, 1910 


From a photograph taken at the Yerkes Observatory 





Comets and Meteors 93 


with great rapidity, completing its revolution in 10 hours, 14 minutes (the day of 
Saturn), the great ball is “bulged out’’ or broadened at the equator and flattened at the 
poles. This oblateness of the sphere is even more marked than in the case of Jupiter. A 
small telescope will show it. 


COMETS AND METEORS 


There is no weighty reason why any amateur astronomer should not be the discoverer of a 
comet. The requisites are a telescope of low power, large field, and generous illumination; a 
good store of pertinacity and patience; and a fair knowledge of the constellations—in order 
that the observer, by reference to the neighboring stars, may be enabled to decide as to the 
fact of motion in a suspected object. If, after several hours, no motion—in reference to 
surrounding stars—be noted, the probabilities are that the object is not a comet but a 
nebula. For almost all comets, especially on our first view of them, look much like 
nebule, having the appearance of small patches of mist. These may never grow much 
brighter, may never show nucleus or tail, and may bring not much of fame or pride 
to the discoverer. But the essential characteristic of a comet may have been found. 
This is the coma, the misty cloud of faintly luminous material of which we have been 
speaking. The essential thing is not a ‘‘tail’’ nor even the nucleus (the bright core, or 
point almost starlike in its brilliance, at the centre of the coma) but the coma itself. 

As we look at the illustrations of a comet we naturally think of it as rushing through 
space with its tail streaming out behind it just as a flame of fire streams backward 
from a hurtling torch. The tail of the comet, however, sometimes goes before it. In 
fact, the tail (if there be a tail) always extends from the comet in the direction 
opposite to the Sun,—so that as a comet approaches the Sun the head precedes the 
tail, but as it leaves the region of the Sun the tail precedes the head. Through causes 
which no one has yet fully explained, the Sun, while powerfully attracting the comet as 
a whole, seems to exert a repulsive force upon the infinitely refined material of which 
the tail is formed. The head or coma of a normal comet is frequently as much as 
100,000 milesin diameter. Manyarefarlarger. The tail ranges in length from 10,000,000 
to 100,000,000 miles; the diameter of the nucleus, or bright point within the head, is 
from 100 to 5000 miles. 

Astronomers differ as to the nature of the stuff or matter of which the nucleus is 
composed. Some have supposed this matter to be made up of swarms of meteors,—or 
extremely small particles, widely separated, glowing with an incandescent heat resulting 
from collisions with one another, or luminous from some form of electrical action. No 
positive knowledge is yet at hand. We do know, however, that the stuff or matter 
of a comet is, on the whole, of almost inconceivable rarity or tenuity, so thin and 
impalpable that probably no harm to us could result from any possible collision with such 
a body. 

Comets which have closed orbits return again, and their return may in many cases be 
predicted. Among these are Encke’s, with a period of 314 years; Swift’s, with a period of 
51% years; Tuttle’s, with a period of 1334 years; and Halley’s, with a period of 76 years. 
The last named is the most famous because it was the first to have its return predicted 
and the first to indicate the feasibility of such calculations. Many of the noblest comets 
of history have not been again identified, either because their orbits are not closed—bearing 
them forever beyond our solar system—or because, though closed, their orbits are so vast 
as to permit their return only after hundreds or even thousands of years. Our illustrations 


94 HH Beginner’s StaraBook 


are chiefly from photographs of Halley’s Comet taken at its recent return. It has returned. 
periodically for many centuries, sharing intimately in some of the critical occasions of 
history, as in the Norman Conquest, A.D. 1066. The opening scenes of Tennyson’s drama, 
Harold, contain some striking and significant references to the strange visitor. For while 





COMET MOREHOUSE, 1908 
Photographs from the Yerkes Observatory ; taken three hours apart 


we now know that comets are altogether harmless to our Earth, they were often supposed 
by the ancients to be the forerunners of calamity if not the symbols of divine displeasure. 
In noting our photographs of the comets, see p. 29 as well as pp. 92, 95, 137, the reader 
should give no regard to the light-streaks that appear on the photographic plate. These 
are traces of the stars. The camera must be adjusted to follow the comet. If the exposure 
must be a long one, as is usually the case, the apparent movement of stars is not likely to 
be at either the same angle or at the same velocity as that of the comet, and the traces 
of the star-images must appear upon the plate. Several types of comets are shown. That 
of Giacobini, p. 29, was remarkable for the large relative size and impressive form of its 
head; that of Morehouse, above, for the relative smallness of the head and the peculiar 
form and striking changes of the tail. 

Of meteors there is little to be said in a volume such as this, because they are of small 
telescopic interest. They are not, of course, real shooting “‘stars,’’ for they are relatively 
very small and they live and perish within our solar system. They “rain a ceaseless rain” 
upon the Earth. Nor do they fall at random out of space, as was once thought. They 
revolve, apparently in swarms, in orbits about the Sun,—some speeding in the same direc- 
tion as the planets, some with motions that are retrograde, and some in orbits that cross 
our own. So rapidly do they move that they enter our atmosphere with a velocity which 
by the force of its impact with the air raises them to a heat of inconceivable intensity. 
The smaller bodies shine for a moment or two and are consumed; the larger fall, and when 





HEAD OF HALLEY’S COMET, MAY 8, 1910 


Reduced from Photograph taken at the Mt. Wilson Solar Observatory 
See also pp. 92 and 137 


95 


96 Hl Beginner's Star-Book 


picked up are called meteorites and aérolites. From about July 20th to Aug. 16th (maximum 
of display Aug. 11th) the earth passes through a swarm of meteors which seem to radiate 
from the direction of the constellation Perseus. They are therefore called ‘the Perseids.”’ 
In November, about the 15th, we meet the Leonids, coming from the apparent direction 
of Leo. The Geminids (Gemini) are seen about December 7th and for some days there- 
after. November 24th is the date for the Andromedes; October 19th, for the Orionids; 
May 6th, for those coming from the region of the star Eta (7) in Aquarius; July 28th, for 
those coming from the region of Delta (6) in Aquarius; April 20th, for those coming from 
the region of Lyra. In counting them, an opera-glass or a field-glass of low power is some- 
times useful, especially in noting those with the lower velocities. The three important 
points to be noted are the number per hour, and the duration and direction of their flight. 
In fixing the direction in the observer’s memory, a cane or wand instantly held in line with 
the meteor’s flight has often proved a convenience. That meteors are the fragmentary 
masses of former, or still existent, comets is now the generally accepted theory of their 
origin. Fuller information as to both classes of objects may be had in the general volumes 
on astronomy mentioned on p. 144,— especially in those by Sir Norman Lockyer and Miss 
Agnes M. Clerke. See, also, p. 143 of this volume under the head of ‘‘ Useful Work for the 
Amateur.” 


“On a starred night Prince Lucifer uprose. 
Tired of his dark dominion swung the fiend 
Above the rolling ball in cloud part screened, 
Where sinners hugged their spectre of repose. 
Poor prey to his hot fit of pride were those. 
And now upon his western wing he leaned, 
Now his huge bulk o’er Afric’s sands careened, 
Now the black planet shadowed Arctic snows. 
Soaring through wider zones that pricked his scars 
With memory of the old revolt from Awe, 
He reached a middle height, and at the stars, 
Which are the brain of heaven, he looked, and sank. 
Around the ancient track marched, rank on rank, 
The army of unalterable law.” 


GEORGE MEREDITH: Lucifer in Starlight. 


OT. Some Instruments of Observation 
THE OPERA-GLASS AND FIELD-GLASS 


SAID a distinguished astronomer, the late R. A. Proctor: “‘I have often seen with 
pleasure the surprise with which the performance even of an opera-glass, well steadied, 
and directed towards certain parts of the heavens, has been witnessed by those who 
have supposed that nothing but an expen- 
sive and colossal telescope could afford any 
views of interest. But a well-constructed 
achromatic telescope of two or three 
inches in aperture will not only supply 
amusement and instruction; it may be 
made to do useful work.’’* Such a state- 
ment is even more applicable to-day than 
when Proctor wrote it. Not only are our 
small telescopes better in quality, but the 
modern opera-glass and field-glass are more 
fully adapted to astronomic uses. 

The opera-glass is not, as is sometimes 
supposed, either a plaything or a toy. Itis 
a serious instrument. While it cannot do Oe Ae eee area 
the work of a great telescope, it can do some things for which the great telescope is 
unfitted. We may remember the retort of the squirrel to the mountain, in Emerson’s 
quaint poem: “If I cannot carry forests on my back, neither can you crack a nut!” 

The opera-glass, because small in size, may be slipped easily into the pocket; and, 
because light in weight, may be handled and used for long periods without fatigue. With 
it one may catch the view of a meteor’s trail more quickly than with a heavier instru- 
ment. It can be always ready. Because its magnifying power is not high, it is less 
easily affected than the telescope by fogs and mists; and, for the same reasons, its use is 
more practicable in travel,—as on shipboard or on a moving train. Moreover, its magni- 
fying power is quite sufficient to be of frequent aid in following a comet, in studying 
brilliant star-fields like those found in the Pleiades and in Orion; and it is of special 
value in helping the amateur observer to trace the outlines of the constellations. Even 
after the telescope has been adopted and is well understood, an opera-glass is often of 
definite service in examining unfamiliar star-fields—especially upon dull or hazy nights— 
in order that the larger instrument may be intelligently directed. 

As with all optical products these vary in quality. There are opera-glasses and opera- 





* Half Hours with the Telescope, by R. A. Proctor, M.A., F.R.A.S.; p. 1; Longmans, Green & Co., New York 
and London, 1868. 


97 


98 A Beginner’s Star=Book 


glasses. Often the same glass that has been used for years at the theatre is also quite 
satisfactory for the study of the stars. The best for this purpose are undoubtedly those 
having large object lenses,—the object lenses are at the end nearest the object viewed; or, 
in other words, the lenses at the large end of the instrument. The larger these are—other 
things being equal—the larger will be 
their light-collecting power. Magni- 
fying power is not so important 
in such a glass as its power to 
show a fairly large field brightly and 
clearly lighted. The beginner should 
be constantly on guard against the 
temptation to exaggerate the 1mpor- 
tance of mere magnifying power. 

I cannot concur in the opinion 
sometimes expressed that it is wise, 
in purchasing an opera-glass, to go 
to odd and out-of-the-way places to 

FIELD-GLASS: PRISM BINOCULAR TYPE secure one. ‘There are doubtless 
excellent glasses to be found in some of these shops. But in going to a regular dealer you 
may not only be reasonably sure your glass is what it is represented to be, but you are 
dealing with one who will have a permanent interest in its quality and service. Excellent 
glasses may be had of the regular dealers at very moderate prices, ranging from $4 or 
$5 to $15 or $20 a pair. 

The optical principles represented in the opera-glass involve, however, certain limi- 
tations as to power. Some glasses magnify but 214 diameters, some magnify 3, some 344 
or 4. But the greater the magnifying power the greater in length must be the tubes or 
cylinders of the instrument. The ordinary field-glass is, accordingly, but an opera-glass 
of greater length; and because the principle of construction is the same as that employed 
by Galileo in his earliest models of the telescope, such an instrument is said to be of the 
“Galilean” type. The Galilean field-glass has greater magnifying power than the opera- 
glass; and, if well made, will present images or pictures of great sharpness and clearness. 
But in some of these instruments the picture is not well lighted or sharply defined except 
at the very centre of the field of view; the field of view is small, at best; and the physical 
weight of glasses of this type is quite large for the magnifying power afforded. When, 
therefore, a magnifying power of 7 or 8 diameters is attempted the Galilean field-glass 
usually becomes too large and bulky for comfortable use. 

There is, however, one modern improvement much to be commended to the purchaser 
who can afford it. This is the device for permitting the adjustment of the glass to vary- 
ing pupillary distances. The eyes are not the same distance apart in all heads, and these 
“jointed bars’? permit the comfortable adaptation of the field-glass to the individual. 
Where the ‘“‘jointed bars’’ cannot be obtained and the frame is therefore rigid, be sure to 
select your glass so that it is suited to the distance between your own eyes. This can be 
easily tested by noting whether the two tubes of the glass present a single field of view. 
The two miniature telescopes of which the field-glass is composed should do good ‘‘team- 
work.’”’ They should show one picture. It is well to select the plainest, simplest 
““finish’’ as the most desirable, especially for outdoor use; and if the instrument be that 
of one of the better manufacturers it will more than justify the amount expended in its 
purchase. 





Anstruments of Observation 99 


THE PRIsM BINOCULAR 


By the invention, however, of the prism binocular, another type of field-glass is now 
available. A new principle has been brought into play. Some sixty years ago a French 
engineer named Porro discovered that through the introduc- 
tion of highly polished glass prisms, at the proper intervals 
within the tubes, the rays of light could be so ‘‘doubled 
back’”’ upon themselves that the optical necessity for the 
increased length demanded by increased power could be elimi- 
nated. High powers could thus be provided for, through 
tubes that might be actually very short. This ingenious sug- 
gestion has now been so broadly adopted that there are 
many kinds of “prism binoculars,’’ several of the different 
““makes’’ representing a high degree of optical refinement. 
They are naturally more expensive in price than glasses of 
the Galilean type. The fitting and polishing of the prisms, 
and the very rigid mechanical construction demanded in the 
body of the instrument, require workmanship of rare experi- 
ence and skill. The Galilean field-glass ranges in price at 
retail from $10 to $20; the better grades of prism binocular 
range from $40 to $75,—though there are some as low as $2 
and some as high as $90. Much depends upon the precise 
model desired. As in the case of the opera-glass, the best 
types for astronomical purposes (costing from $40 to $75) 
are those possessing large object lenses. The large object 
lenses, as already explained, ensure for the instrument a large 
light-collecting capacity. This increases the pleasure in its yey power, PRISM BIN CcUran: 
use at night and also gives it a high penetrating power under FIELD-GLASS 
adverse conditions of light and air. eT ale tLe 

Not only are these instruments smaller, in proportion to their magnifying power, than 
the Galilean glass, but they present a large field of view, well defined, and clearly and evenly 
lighted to the very edge of the picture. The optical conditions, however, which result 
in the relative reduction of both light and field with the increase in magnifying power are 
inexorable, and apply here also in spite of the superiority of the prism binocular to the 
Galilean glass. Because of these conditions it is not wise to select, even in a prism binocu- 
lar, a power in excess of 6 or 7 or 8 diameters if the instrument is to be given “‘free-hand”’ 
use,—is to be used without some form of artificial support. For we must also bear in mind 
the fact that just as your field-glass magnifies the objects to which you direct it, it must also 
magnify—and precisely to the same extent—the trembling or unsteadiness of the directing 
hand. The higher the magnifying power you employ the more difficult you will find it to 
hold your instrument ‘‘steady,’’—unless you use some form of artificial support. The 
various magnifying powers—as 6X, 7X, 8X, 9X—are usually specified upon the frame 
or body of the glass. The symbol X means “times” and represents the tumes an object 
is magnified, or the extent to which the apparent diameter of an object is increased. In 
the same way we say that a glass or telescope has a power of 8 or I5 or 100 diameters. 
This means that the instrument increases to this extent the apparent diameter of the 
object. 

Where, however, some form of artificial support for the glass can be purchased or devised, 





100 H Beginner’s Star=-Book 


much satisfaction can be found in powers as high as 10, I2, 15, oreven 18. Prism binoculars 
may be had in all these magnifications and if care be taken to select a model having large 
object lenses, and thus affording abundant light, such a glass has some advantages over the 
small telescope. Among these advantages we cannot include economy, for they are more 
expensive than some telescopes, ranging in price from $60 to $90. They do, however, 
afford the pleasure and comfort of ‘‘binocular’’ as opposed to ‘‘monocular’’ vision; that 
is to say, we may use both eyes naturally and easily in looking through them. A power 
under 20 diameters, however, will not show the ring formation of Saturn, or many of the 
double stars. But such a glass, even if it have only a power of 10, will divide a few of the 
double stars, will show the four larger satellites of Jupiter, the crescent phase of Venus, and 
beautiful views of the more conspicuous features on the surface of our own moon. Metal 
holders or clamps may be purchased of almost any optician, either with an accompanying 
metal support, or to be used in adjusting the glass to any ordinary camera tripod. The 
large object lenses provided with instruments of this type make them especially useful 
in looking for comets or in viewing brilliant star-groups such as the Pleiades. 


THE Spy-GLAss OR DRAW-TELESCOPE 


This familiar glass, the ordinary hand telescope of the mariner and the hunter, affords 
neither the comfort of “‘binocular” vision nor the high magnifying power of the regular 
astronomical instrument, but it is inexpensive and it will often do good work. For views 
of the wider double stars, for the coarser star-clusters, and for the study of our own moon 
and of the four larger moons of Jupiter, such telescopes are usually quite adequate. Their 
eyepieces present an ‘‘erected’’ image—a term we will explain a little later on—and so 
their objects in the field of view are “‘right-side-up,’’ as in an opera-glass or a field-glass, 
but this field of view is small and not well lighted. Unfortunately the eyepieces furnished 
with them are often of higher magnifying power than the size of the object lens and the 
construction of the instrument will justify, but the manufacturers are gradually correct- 
ing this error. There has been prevalent a natural but thoroughly unintelligent demand 
on the part of the public for “high’”’ magnifying powers in all of our popular field-glasses 
and telescopes. Manufacturers long felt that they must yield to this demand, though 
they knew it to be self-destructive (a magnifying power so high as to compromise the 
pleasure-giving quality of the telescope is ‘‘bad business’’ commercially as well as astro- 
nomically) but happily a change is now at hand. 

In using a spy-glass, or hand telescope, remember that to do any sort of satisfactory 
work it must be steadily held. The metal clamps used for fixing a field-glass to a tripod 
are just as well adapted to the spy-glass. If these are thought to be too expensive, the 
amateur who possesses a little skill at wood-working can make his own mounting, at very 
low cost and with small trouble. A forked staff set in the ground, the telescope resting 
in the fork, is better than nothing. At the section of the telescope at which the instrument 
is grasped by the metal clamp or by the fork a piece of soft cloth or chamois-skin should 
be wrapped about the tube, to prevent its polish from being injured. This piece of soft 
leather or cloth may be held by a few stitches or by a couple of tight rubber bands. 

This type of telescope is usually made in sections or joints, the smaller sliding down into 
the larger when the instrument is closed. The instrument must, of course, be extended or 
drawn out for use in observation—hence the name ‘‘draw-telescope’’ is often applied to it. 
A three-draw telescope or a four-draw telescope is one having three or four, as the case 
may be, of these several sections. The focusing is accomplished by sliding in or out the 


Instruments of Observation 10I 


section containing the eyepiece. Telescopes of this type will not, of course, give the 
satisfaction afforded by instruments regularly mounted on tripod stands and provided 
with one or more regular astronomical eyepieces, but they are inexpensive, easily carried 
about, and capable—within their range—of giving a great deal of pleasure to the beginner. 
Their prices range from $5 to $50 according to quality and size. 


THE ASTRONOMICAL TELESCOPE 


Portable telescopes mechanically mounted on tripod stands may be had in almost any 
size from an ‘‘aperture”’ of 114 inches to 5 inches. The ‘‘aperture”’ (literally = opening, or 
space through which light passes) of a telescope represents the surface diameter of the 
object lens, or the “‘objective.’’ The object lens or objective of the telescope, as already 
explained, is at the large end; the lens at the small end is called the “‘ocular”’ or sometimes— 
in a general sense—the eyepiece. The size of the telescope is usually described in terms of 
the objective,—a ‘‘2-inch”’ is a telescope with the objective 2 inches in diameter; a 
“‘3-inch”’ is a telescope having an object lens 3 inches in diameter, etc. Telescopes 
are also classified as to type or kind as “‘reflectors’’ and ‘‘refractors.’’ The reflectors are 
the better for such work as astronomical photography; the refractor is the type found in 
most general use, especially among amateur observers. Moreover, the greater achieve- 
ments in observation have been thus far accomplished by instruments of this kind. The 
famous 36-inch telescope of the Lick Observatory and the 40-inch telescope of the Yerkes 
Observatory are both refractors. This book deals exclusively with the using of small 
refractors, inasmuch as this is the type of instrument found in the stock of the average 
optician and used in practical work by the larger number of observers;—but those posses- 
sing reflectors will find the directions and instructions easily adapted to their instruments. 

A telescope has but one objective or object lens, but it may have several eyepieces. 
One eyepiece may be removed to make place for another; the object lens, however, should 
never be removed, except at long intervals for cleaning: we will speak below, see note 9, p. III, 
of the proper cleaning of lenses. If you find a few small ‘“‘bubbles’’ in the glass of the 
objective these need cause you no concern. They are often found in glass of the highest 
quality, and—unless present in large numbers—they will not affect the optical qualities 
of any telescope that is in other respects a good one. The telescopes of well-known makers 
are, as a rule, carefully tested before leaving the factory, for a poor instrument is a poor 
advertisement. The beginner may usually be sure, therefore, that his telescope is all right. 
Suggestions for the testing of objectives are found in some volumes, but one who is using a 
telescope for the first time is seldom able to apply these instructions successfully. They 
have often caused more anxiety than aid. Upon the other hand, helpful advice may often 
be had from observers of larger experience. There is a fine esprit de corps among amateur 
astronomers and those who have met and solved their telescope-problems are usually glad 
to be of service to those who are entering the fellowship. 

Yet it is true that the user of a telescope is more or less bored by such enquiries as 
“How far can you see with it?’’ One may well retort, ‘I can see no farther with it than 
without it!’’—for in beholding some of the brighter stars with the unaided eyes we are 
seeing to the limit of mental comprehension,—a distance which if stated in English miles 
could not be expressed in twenty million consecutive human lifetimes, if every breath of 
each were to represent a mile. The value of a telescope cannot be expressed in terms 
of the linear distance which it can penetrate. Nor can it be well expressed in the terms 
of mere magnifying power, for the highest magnifying power optically possible to it may 


102 El Beginner’s Star2Book 


be—because of the conditions of the atmosphere or the limitations of the eye—altogether 
useless from a practical standpoint. What, then, does a telescope do for us? It does 
have both a penetrating and a magnifying power, but its chief function is the collecting of 
light for the eye,—illumination. No amount of magnifying will prove of service to us if the 
mere enlargement of the size of the image is not coincident with its adequate illumination 
in the field of view. And in the case of the stellar world, the distance of which is optically 
and practically at infinity, the illumination of the field of view is the chief function of tele- 
scopic aid. JI here make no reference to the telescope scientifically mounted as an instrument 
of precision for the measuring of angles, etc. I refer to the telescope in average hands. 

The observer in attempting to see and to study the familiar objects of astronomic 
interest is constantly forced to realize that merely increasing the size of an image may actu- 
ally prevent his seeing it, for the increase in magnifying power necessarily involves not 
only the reduction of the size of the field of view but the proportionate shutting out of the 
light needed for its study. Let us therefore first try to appreciate the telescope’s light- 
collecting power. This is proportionate, as we have seen, to the size of the object glass. 
The diameter of the eye’s pupil is about } of an inch; and working with the formula that 
“the light-gathering powers of the eye and the telescope are to each other as the squares of 
their apertures’’ we find that a 2-inch object glass will gather 100 times more light than 
the natural eye. To get the light-collecting power of an object lens as compared with the 
eye, we thus divide the square of the diameter of the lens by the square of +; or we may 
merely take the number 25 and multiply this number by the square of the diameter. 
Thus, a 3-inch objective will collect 225 times as much light (9 X25) as the unaided eye; the 
4-inch telescope will collect 400 times as much (16X25), etc. A 3-inch objective thus gives 
more than twice as much light as a 2-inch, and a 4-inch nearly twice as much as a 3-inch. 

The object lens, receiving its normal share of light, and receiving with it an image 
from without, sends both down the tube of the telescope to be received by the eyepiece. 
The amount of light, while generous, is fixed in quantity. But the image, upon the 
eye, 1s not yet fixed in size; it can be varied in size by the different magnifying powers rep- 
resented in the different oculars. If the power of the eyepiece be great the light received 
must be spread over a large image and the impression must be dim; if the power be small 
the light is not so much spread out, or diffused; and, as the parts or factors of the image lie 
closer together, the light may fall upon the whole with more of concentration. The re- 
sulting image is smaller but brighter. It is thus that low magnifying powers involve a 
relative intensity of illumination, and high magnifying powers involve a relative diffusion, or 
loss, of light. This is not the whole story. Questions of optical theory lie outside the prov- 
ince of this book. It is well, however, for the beginner to appreciate a few of the reasons 
why, as I have said, the attempt to increase the size of an image in a particular telescope may 
actually prevent our seeing it. The practical astronomer has always laid stress, therefore, 
upon the maxim that ‘‘the highest power which can be used with advantage is the lowest 
power which will show the object.’’ In other words, if a power of 50 will show you the thing 
for which you seek, there is no gain and much loss in crowding on a power of 75 or 100. 


THE ASTRONOMICAL OR REVERSING EYEPIECE 


Practically all telescopes of standard quality are provided with two or more astronomical 
eyepieces. They are usually provided also with a terrestrial eyepiece for viewing ob- 
jects on land or sea by daylight. This latter is in the longer of the sliding tubes that slip 
in and out of the main body of the instrument. Removing this tube with its eyepiece, 


Instruments of Observation 103 


the shorter tube may be slipped into its place. This shorter tube carries the astronomical 
eyepieces; they may be slipped or screwed into it, and are interchangeable. Upon 
each a cap of dark-colored glass is sometimes found. This is for use in viewing the 
Sun (see, however, par. 2, p. 64) and should be removed, of course, when viewing other 
objects. First learn to focus 
with the astronomical eyepieces 
by daylight, directing the tele- 
scope to some distant object, 
preferably on land rather than 
at sea. Begin with the eyepiece 
of lowest power. On looking 
through it the beginner will note 
that the image is inverted, or 
“upside-down.”’ This is no 
reason for indignantly return- 
ing the telescope to the dealer 
as defective,—a course that has 
been followed more than once. 
All astronomical eyepieces show 
aninvertedimage. The image is 
so presented by the object lens. 
It reaches the eyepiece upside- 
down. It is a simple matter to 
erect it, if we so desire. This is 
done, indeed, by the terrestria! 
eyepiece, for by daylight, and in 
viewing objects upon the earth, it 
is confusing and disconcerting to 
have to view them upside-down. 
But in the sky, where there is no 
scene of closely related objects to 
which we must mentally adjust 
ourselves, an inverted image 
makes practically no difference TELESCOPE—MODEL A 

tous. We soon grow used to it. de Ee Ne 

And such inconvenience as it may cause is more than offset by the fact that with the image 
inverted we can enjoy more of the light-collecting power of the telescope. For the erection 
of the image additional lenses must be used—this is one reason why the terrestrial eyepiece 
is longer and is more expensive than the astronomical—and these additional lenses for the 
erection of the image necessarily absorb a portion of the light. 

We have spoken of the fact that the two or more astronomical eyepieces usually pro- 
vided with each telescope represent different magnifying powers. But it is well to remem- 
ber that the magnifying power of the telescope is also determined, in part, by the size of 
the object lens.* In other words, the result is due to a combination of the lenses at both 


» 





* Each lens has always a fixed “focal length.” The focal length of a lens represents the linear distance between 
the centre of the lens and its focus. The magnifying power of a telescope is that of the eyepiece and the object lens 
in combination; and this power equals the focal length of the objective divided by that of the eyepiece. For 
example, if the focal length of the objective is 38 inches, and the focal length of the eyepiece is half an inch, the 
magnifying power of the combination is 38 +0.50=76. 


104 A Beginner's Star-Book 


ends of the instrument. The objective, however, is fixed; so we secure our changes in 
magnifying power by changing the eyepieces. And as this is easily and quickly done we 
fall naturally into the habit of speaking:of ‘‘40-power eyepieces’’ or ‘‘eyepieces of 60 
power.”’ This habit is a matter of convenience. It does not become an inconvenience 
unless we forget the truth of the case in ordering a new eyepiece, and merely send for a 
‘‘50-power eyepiece.’’ No one will know precisely what eyepiece we wish unless we 
also specify the size of the object lens, the length of the telescope tube, and—if possible— 
the name of the maker. For an eyepiece that will give a magnifying power of 50 on a 


3-inch telescope, will give less than 50 on a 2-inch and more than 50 on a 4-inch. 
WHAT MAGNIFYING POWERS? 


In selecting the astronomical eyepieces for a small telescope it is well to have at least 
two—and, if the purse permit, a third or evena fourth. Two, however, should be regarded 
as essential,—one a low-power, for easy double stars, for star-clusters, comets, nebule, 
general star-fields like the Milky Way, and for all objects presenting an extended image. 
Here the primary requisites are abundant light and a generous field of view,—conditions 
afforded by low powers and rendered impossible with high powers. An eyepiece of high 
power will often prove useful for difficult double stars, and for the study of detail upon 
Sun, moon, and planets. 

Between the highest and lowest powers it is well, when feasible, to have an intermediate 
eyepiece, for use under special conditions that may arise while the observer works. At- 
mospheric difficulties may make the highest power useless on a night when the planets are 
of special interest; or a double star, too ‘“‘close’’ for the lowest power, may require more 
light than high magnification will permit. Indeed the intelligent observer will find that 
one of the most interesting phases of his work will be the adaptation of his instrument, 
from object to object or from hour to hour, to the immediate conditions with which he 
deals. No absolutely rigid rules may be imposed. 

It may be helpful, however, to indicate a series of eyepieces for the sizes of telescopes 
in popular use. This is here done, distinctly upon the assumption that these suggestions 
are only approximate and that a variation of a few diameters in any particular case should 
not be a cause for rejecting a telescope. Indeed, a manufacturer in providing the optical 
equipment for his instruments may often prove a better judge than any one else. In 
some cases, however, the manufacturer does not specify the powers of the eyepieces, 
merely offering a given number (two, or three, or four, etc.) with the instrument,—and 
leaving it to the purchaser to choose the powers. In such cases, then, these suggestions 
may prove useful. In selecting astronomical eyepieces the best two powers for a 2-inch 
telescope would be 25 and 75x; the best three powers would be 25X, 60X, 75X. For 
a 24-inch the best two would be 30X, 85X; the best three, 30X, 65X, 85X. Fora 
214-inch the best two, 35,95; the best three, 35X,70X,95X. Fora 24-inch the best 
tw0, "40 X7 100 x; the: peststhree e410 as). eOU 

For a 3-inch telescope the best two powers would be 45X and 115%; the best three, 
45X, 75%, 115X; the best four, 45X, 75X, 115, 150X. For a 34-inch the best two, 
65 X and 160X; the best three, 65,95, 160; the best four, 65X,95X, 140X, 160X. 
For a 4-inch telescope the best three, 70X, 150X, 230X; the best four, 70X, 100X, 
150X, 230; the best five, 70X, 100X, 150X, 230X, 285. 

The series just outlined might be continued indefinitely; but for other instruments 
the observer will find it easy to apply the general principles suggested by the examples 





Instruments of Observation 105 


cited. Ina number of cases I should have suggested, for the lowest power, eyepieces even 
lower than the ones indicated, but it is not always easy to secure them. The manufac- 
turers have been under such continuous and general pressure for high powers, and an 
uninstructed public has been so prone to test every telescope by its mere ability to carry 
high magnifications, that the 
makers have not been wholly to 
blame. But powers for each in- 
strument as low as the lowest 
prescribed above may usually be 
obtained, and are fairly satisfac- 
tory. The optical limit of lowest 
power is, of course, fixed by the 
light-receiving capacity of the eye. 
The diameter of the average pupil 
being 4 of an inch, as we have 
seen, we must employ a magnify- 
ing power of at least 5 for every 
inch of aperture. The low-limit 
of power for a 3-inch telescope 
would therefore be 15X. This 
is the theoretic limit. Practi- 
cally, however, there are few eyes 
that can well utilize so large an 
amount of light. There is also a 
high-power limit. Astronomers 
have frequently placed this at 100 
for every inch of aperture. Upon 
this basis an eyepiece magnifying 
300 times may be used on a 3-inch 
telescope and a power of 200 ona 
2-inch. Formal tables showing, 
upon this basis, the double stars 
that different telescopes will divide 
have actually been published in 
reputable books. Nothing could 
be more misleading, especially to 
the beginner. ‘‘Indeed’”’ says TELESCOPE—MODEL B 

Newcomb, “‘it is doubtful if any eee ace re 

real advantage is gained beyond 60 to the inch.’’* As the context shows, Newcomb has 
special reference to a large telescope, 24 inches in aperture, and, as he hastens to 
declare, his ‘‘remarks apply to the most perfect telescopes used under the most favor- 
able circumstances.’”’ He then proceeds, in terms too technical for quotation here, 
to describe some of the inevitable limitations of the telescope. We will deal below, in 
showing the advantages of low powers, with some of the simpler of these difficulties. 
It should also be said that the beginner does not have, with the astronomer, the 
advantages of training,—the trained eye and mind and hand. In the light, there- 
fore, of these considerations it should be clear that the average amateur observer, 

* Popular Astronomy, by Simon Newcomb, LL.D.; New York, American Book Co., p. 144. 





106 Zl Beginner’s StarzBook 


especially at the beginning, cannot use to advantage a power of over 35 or 40 for every 
inch of aperture. This is the maximum, from the standpoint of practical experience. 
And in most cases the beginner will do well, especially at first, to work with eyepieces 
giving powers still lower. He will not thus see less than with higher powers; he will actually 
see more, and what he does see will be seen with greater clearness and with far greater ease 
and pleasure. As he gains in experience he can begin the use of eyepieces of higher power. 


THE TELESCOPE MOUNTING 


The telescope tube is supported by a stand or tripod. Sometimes the instrument is 
merely provided with a stand of the “pillar and claw”’ type as shown in our illustration 
called Model A. This form of support is intended for use upon a table or upon a broad 
window sill. For packing or storing with the telescope, it has decided advantages but it is 
not usually a satisfactory model for serious work. Many of its disadvantages, however, 
can be overcome by careful managing. If it be used upon a table, see that the table rests 
solidly and squarely on the ground or floor so that every possible source of unsteadiness 
may be provided against. Telescopes of this general type may be had of a number of 
makers and dealers, in sizes ranging from a ‘‘2-inch”’ to a “‘3-inch.”’ 

The telescope marked here as Model B represents a more efficient type of tripod and 
is not much more expensive than the preceding. By far the greatest number of small 
portable instruments are mounted in this way. Each manufacturer varies the type a 
little, some making the tripods lighter or heavier than others, and securing the two motions 
necessary—a cross motion and a motion up and down—by different mechanisms. But all 
such mountings, from whatever maker, are extremely simple in design, are quickly under- 
stood and easily handled. While Model C represents the same general principle, it is 
heavier, its structure is more stable, and it possesses a more elaborate mechanism for 
increasing or decreasing the height of the telescope. The instrument here shown is pro- 
vided with a “‘finder,’’—a miniature telescope at the eyepiece end of the tube for aiding 
the observer in bringing objects into the field of view; § 13, p. 112. Tripods of this type 
are less portable than Models A and B but possess greater rigidity and steadiness. 

The models thus far mentioned, A, B, and C, represent, in principle, what is called an 
“alt-azimuth’’ mounting, a mounting permitting a motion in altitude and a motion 
“in azimuth”’ (or a motion up and down and right to left). The two motions permit 
the direction of the telescope to any point within convenient range of the observer. In 
Model D, however, we find the two motions necessary to the telescope secured in a some- 
what different way. This represents what is known as an ‘‘equyatorial’’ mounting. 
Here, when the instrument is properly placed and adjusted, the fundamental axis is 
jixed parallel with the axis of the earth, running north to south. Free movements on the 
other axes of the instrument now give to the telescope the two motions provided by the 
preceding models. Assuming, for example, that the large end of our instrument points 
south, an observer stationed at the eyepiece will be able, when a star to southward has 
been brought into the field of view, to follow it in its course with only one motion of the 
telescope, the motion from east to west. This work can also be performed by an ad- 
ditional attachment called a ‘‘slow motion”’; note the rod extending outward between the 
tripod and the eyepiece. And even this function is discharged, in instruments still more 
elaborate, by a ‘‘driving-clock’’ which, moving the tube in correspondence with the diurnal 
motion of the earth, enables the observer without effort to follow the course of the object 
in the sky. The ‘equatorial’? mounting, with or without a driving-clock, is often pro- 


b 


Instruments of Observation 107 


vided with ‘‘hour circles.” Such an equipment ensures the accurate direction of the 
telescope to any object in the heavens, whether or not it may be seen by the unaided 
eye, provided its Right Ascension and Declination (the astronomical equivalents of 
longitude and latitude) are known. By a system of graduated circles adjusted to 
the axes of the telescope the instrument may 
be directed first to the proper Declination 
of the object, and clamped; it may then be 
turned to the object’s Right Ascension (in 
hours, minutes, etc.,—see note 14, p. 32). 
The star will thus be brought within, or 
very nearly within, the field of view. In- 
deed it should now be precisely in the field 
of the telescope if all the conditions of the 
case are accurately met. As most of the 
readers of this book will not possess instru- 
ments with hour circles I merely refer those 
who wish to make further study of their 
use to the volumes listed in the footnote.* 
To meet, however, the needs of instru- 
ments so equipped the places of the objects 
listed in the Observer’s Catalogue of the 
present volume are indicated by Right 
Ascension and Declination, as well as by 
constellations. Such references are also of 
value to those who may use the charts of 
the celestial sphere at the close of the 
book, or who may desire to make use of 
celestial globes or larger star maps. In the 
location of the objects of observation, even 
when the telescope is without hour circles 
and not equatorially mounted, such refer- 
ences become increasingly helpful. 

Which of these various types of mounting 
shall the beginner purchase? The answer— 
for all cases—is not easily given. Each type TELESCOPE—MODEL CG 
has its strong points. Model D, if fitted Alt-Azimuth Mounting 
with hour circles, should have the preference for advanced students, even though the 
instrument be without a driving-clock. But, in order to possess any real advantage 
over the simpler mounting represented in Models B or C, it must be accurately adjusted 
for latitude; it is heavier, more complicated, and not so easily managed. For the beginner, 
therefore, I do not hesitate to recommend the general form shown in Models B and C. 
These are purely illustrative. Both types of mounting are made by many different 
manufacturers in a number of designs; all representing the same principle of construction. 
The alt-azimuth type is less expensive as well as less complicated than the equatorial, 
and it is adapted, if well made, to all the ordinary needs of the amateur. 





* See Chambers’ Handbook of Astronomy, vol. i., the Oxford Press, 4th Edition, New York and London; Gibson’s 
Amateur Observer’s Handbook, Longmans, Green & Co., New York and London, p. 36 fol.; Todd’s New Astronomy, 
New York, American Book Co., p. 53. 


108 H Beginner’s Star2Book 
THE TELESCOPE FOR THE SCHOOL 


In teaching the circles of the celestial sphere and in illustrating the theory of the science, 
the instructor may desire an ‘‘equatorial’’ mounting, but in the practical work of observa- 
tion, in introducing others—by simple object-lessons—to the pleasure and practice of 
viewing the things of the sky, the less elaborate mounting will meet the requirements 
even of the teacher. For high-schools and colleges I would strongly advise, where finan- 
cially possible, a telescopic equipment of three or four small instruments, rather than one 
very large one more elaborately mounted. Of this group of telescopes, the largest may have 
an aperture of 334 or 4 inches and be mounted equatorially (if desired) ; the others may be 
of 3 inches in aperture (or even smaller) and on alt-azimuth mountings. Such an equipment, 
while not meeting an ambitious desire for an ‘‘observatory,’’ will do far more than a great 
observatory instrument for the actual needs of the students. These, at least in earlier 
years, can hardly expect to become astronomers in the technical sense, but they should 
be permitted to share the interests and enthusiasms that follow from the direct personal 
observation of the familiar celestial objects. A little experience of this kind will often 
awaken ambitions for higher and broader work; and it has its illustrative value for teachers 
as well as scholars. An equipment of small instruments has the following advantages over 
a single large expensive telescope: 

(1) It is possible in many cases in which the large telescope with elaborate mounting 
is impossible; many a small institution which has no local provision for the large telescope 
can provide for the storage and keeping of a number of smaller ones. 

(2) This equipment will permit the simultaneous instruction. within a short period of 
time, of a larger number of observers. 

(3) With it, the really interested teacher can more quickly train adequate assistants 
from volunteers among the older pupils or from among associate teachers—if assistants 
should be necessary. 

(4) The equipment of smaller instruments may be quickly unpacked and adjusted for 
use by one or two of the older pupils,—or even by an intelligent janitor, if need be. When 
work is completed the telescopes may be as quickly repacked, and stored. 

(5) The suggested equipment is far less expensive than a single large telescope on a 
stationary stand with an elaborate mounting. 

(6) Such a provision, even in institutions where there are large telescopes or observa- 
tory work, will free these larger instruments for their proper service under the observatory 
staff, and yet provide for the legitimate desire on the part of the students and others to 
see for themselves the objects of astronomical interest. Nearly all the characteristic 
objects of observation, see p. 3, can be seen by the beginner with far greater satisfaction in 
a small telescope than is commonly supposed. 

(7) The experience acquired will be all the more useful because gained from practise 
with such instruments as the average student may some day hope to possess. 

(8) The problem of bringing the telescope into the work or the recreation of the average 
school often resolves itself into the practical problem of finding the teacher who can under- 
take it. The plan suggested—a small group of several smaller instruments simply mounted 
—requires no special training. Such an equipment can be readily utilized. 


FIRST OBSERVATIONS—THE ADVANTAGE OF LOW POWERS 


The telescope is usually delivered to the purchaser in a box; the tripod being packed 
separately. In unpacking the metal parts from the box, note how the pieces lie, in order 


Instruments of Observation 109 


that they may be easily replaced when you desire to return the instrument to the case. 
Fixing the tripod in the open air for your first observations, see that its feet are eve 2 
spread and that it is truly centred. All that contributes to its steadiness wit 
see; all that interferes with its stability will make good seeinz ¢’ ~~~ 
of the mounting, it should be strong and secur 
A good, rigid support for the instrument is , 
fundamental importance. 

Almost the first question to arise will 
“What shall we look at?’’ Choose at f 
something quite easy. Let it be at night 
possible; the Sun is a poor first object. If 
moon is in the sky, turn first to that. If 
time be a winter’s evening and Orion be 
the sky, try an easy double star,—Delta (6), 
top star of the Hunter’s belt. See the K 
Mapepedi or 45. The star Zeta (¢) in 
Great Dipper, see any northward Key-Map, 
also a fine first object. If the season be the 1. 
spring or early summer, try the star marked B 
(8) im Scorpius; pp. 53 and 57. If one of | 
planets (Jupiter or Saturn) be well placed 
observation, these are also superb first objec 
see pp. 88 and 91. Mars and Venus are not 
“‘consistently’’ easy. 

After removing the brass cap from the | 
end of the instrument, try to get a 
focus on the object, using the astronor 
eyepiece of lowest power,—the eyepiece 
the largest aperture, and with the larges 
posure of glass on its interior surface. 
you look through the telescope trying to 
and view your first objects, you will pert 
be more or less baffled by certain troublesc 
impressions. The statement of these w 
illustrate the reasons for the repeated wart 
ings to the beginner against high magnifying’ 
powers. 

If it were optically possible for the telescope to magnify the object aiuve, and to preserve 
it as a large image in a large well-lighted field, then we should want our magnifying power 
high, indeed the very highest. But this is not possible. Optically, there are some things 
as impossible to a telescope as for a good watch to tick seventy seconds to the minute. In 
magnifying the object, the very power used reduces the field of view in which it lies, the 
amount of light which illuminates this field, and magnifies not the object alone but every 
factor which involves or affects it as an image. The impressions to which I have referred 
are, therefore: 

I. The impression that the world into which you are peering is dark, gloomy, and 
tractless. This impression is the more intensified, the higher the power you employ. 

2. The impression, after you begin to see your way through your telescope, that the 







































I1O EH Beginner’s StarzBook 


circles or areas covered by your instrument are pitifully small. The smallness of the field 
rou command makes it hard to find the object you are seeking. The field becomes smaller 
inding things becomes harder with the increase of magnification. 

Mt. that an object once found is wilfully determined to flit from the field 
urtly due to the unsteadiness of your hand. Just as 
it will also magnify by 100 times, every touch 
caused by the wind or by heavy walking near 
ler these exaggerations of motion. 

nd is removed and all is still, that the object 
uch of the hand, no unsteadiness, no vibration, 
ere is one motion, however, that we may have 
F of the sky, however stable they may be, seem 
This is due to the revolution of the earth on its 
superficially, very rapid; but multiply it by 100, 
nt motion of the stars or moon or sun is thus 
such objects must move across that little circle 
escope. 
to follow an object in the field of view and to 
rately ‘‘contrary,’’ shifting to right or left ina 
tion of the hand. This is based upon fact; all 
astronomical telescope. The fact cannot be 
ly we are to lose the object by small false direc- 
ge field and permit an easier mental adjustment 








































at once by the use of eyepieces of low power, 
ner can begin without a sense of despair and 
} sense of conquest will rapidly increase; and, 
Pin his instrument. He will also find that he 
with advantage—changing his eyepieces and 
o different objects and to varying conditions. 


FICAL NOTES. 


S be found attached to the astronomical eye- 
Dun. It should be unscrewed and removed from 
ee also p. 64. 

meter while seated. Use an ordinary straight-back 
chair. Take imme and the necessary care to place yourself in a comfortable position. 
Strained postures and inconvenient attitudes are directly embarrassing to clear vision. 

3. Be deliberate. Try not to hurry from object to object. Look with the mind as 
well as with the eye; this will help the eye as well as the mind. Try to reflect quietly 
upon the object under observation, returning to it repeatedly and noting any special 
peculiarities that may suggest themselves. 

4. Street lights are sometimes a sore trial, especially when seeking to view objects 
near the horizon. A small sheet of cardboard slipped over the eyepiece end of the tele- 
scope will often prove a protection from their interference. Access to a good roof is an 
even better means of escape from such annoyances. 

5. Work from smaller tasks to greater. The beginner may keep himself in a state of 





al 


Instruments of Observation III 


nervous discontent by a ceaseless expenditure of energy in the pursuit of objects just at 
the limit of visibility. Or he may take a wiser course, and prepare for these tests of vision 
by first learning to appreciate the many interesting objects within the normal capacity 
of his eye and his instrument. 

6. In winter it is advisable to be warmly wrapped—for the physical exercise which so 
often protects us from exposure is missing while we are seated at the telescope. There 
are many observers who do not scorn the use of a hot brick as a foot-warmer. This if 
well-wrapped will keep warm for some time; and, when its heat is gone, another may be 
substituted. 

7. To the beginner, the finding of objects with the telescope will at first seem difficult. 
If the eyepiece of lowest power is used, this will afford a wide and well lighted field of view 
and the object can be located more easily: a higher power, if desired, may then be sub- 
stituted without “‘losing’’ the object. A slight re-focusing will be necessary. As experi- 
ence increases, the finding of the desired objects becomes less difficult and is quickly 
accomplished. 

8. It is usually best to meet the problem of ‘“‘thick’’ weather by retreat,—unless you 
have much time to waste and much good temper to employ. As the telescope magnifies 
mist and fog as well as the objects of interest, it is at its worst under such conditions. If 
one will persist in working, and the mist be not excessive, the best objects under such con- 
ditions are the moon and the brighter planets, particularly Saturn—f these be in the sky. 
Whatever the atmospheric conditions, it is well—befcre beginning observations—to make 
a brief list of the objects to be noted. This will serve as a working memorandum and 
will usually save time. Begin with ‘‘easy”’ objects; not attempting things more difficult 
till the eye has been accustomed to the darkness. 

9g. Cleaning the lenses of an instrument is sometimes necessary. But it is best to use 
your lenses so carefully—protecting them from dust etc.—that this necessity may be rare. 
They bear a high polish. This may be seriously damaged by injudicious wiping and rub- 
bing. Scratches are far worse than a little dust. If dust accumulates remove it gently 
with a very soft camel’s-hair brush, such a brush as may be bought for five cents at any 
druggist’s. Special paper for cleaning lenses is often found at the optician’s. If of the 
very best quality it may be tried, but much of it is worse than useless. The lenses may 
sometimes be dusted off gently with an old soft cambric handkerchief. The objective 
may be unscrewed from the tube, if absolutely necessary, but the two lenses of which 
it is composed should never be taken apart except by the manufacturer. 

10. The habit of pointing a telescope from the window of a room is not to be com- 
mended. Still less should a telescope be pointed through a pane of glass, however clear. 
Distortion must result. The instrument should be taken into the “‘open,’’ even if one 
can do no better than place it on a veranda. If this be impossible and a window must be 
used, all light in the room should be turned out, and time should be given for the pupil of 
the eye to grow accustomed to the dark. In the dark the pupil grows larger and the eye 
keener. The temperature in the room should also be permitted—if possible—to approxi- 
mate the temperature outdoors, if the telescope is to do its best work. The larger the 
instrument, the more need there is to let the air in the tube come to the temperature of 
the air outside, that the images seen in the telescope may be steady and clear. 

Ii. For this reason it is well to permit the telescope to ‘‘cocl off’’ for a few minutes, 
if taken from a warm room in winter and set up outside. Time should also be given to 
the pupil of the eye to dilate in the duller light of the out-of-doors. Good work cannot 
be done with an eye contracted by the illumination of a brilliantly lighted room, peering 


112 H Beginner’s Star-Book 


through a telescope in which the hot air is in process of ‘‘boiling-down”’ to the temperature 
of the outer cold. Sir John Herschel, before attempting to verify his father’s observations 
on the satellites of Uranus, kept his eyes in total darkness for fifteen minutes. Such extreme 
precautions are not necessary with small instruments; but the general suggestion is 
important. 

12. The beginner will sometimes feel the telescope to be a strain upon the eyes. 
Closing one eye while looking through the instrument with the other eye is at first a weari- 
ness to both. This weariness often wrongly suggests that something is the matter with 
the eyes. These difficulties, however, are almost entirely muscular. The proper muscles 
soon become used to the new way of seeing; and the observer soon finds that he can use 
his instrument for long periods with no sense of strain or discomfort. Near-sighted observ- 
ers need not retain their glasses; the instrument, with proper focusing, will correct the 
difficulty: the eyepiece should be pushed a little farther into the tube. Even with normal 
eyes the one used most actively may be soon wearied. If so, it may be given brief intervals 
of rest, and the need for these will decrease as experience grows. A few observers find that 
an eye-cap of dark cloth over the unused eye is an advantage. One needs to avoid the 
undue exhaustion of the nervous and muscular forces of the eye, but this danger is no 
greater at the telescope than at any other interesting work. In many cases the vision is 
stimulated, trained, and positively improved. 

13. The optical equipment of a telescope usually includes at least one terrestrial 
and two or more astronomical eyepieces. If the terrestrial eyepiece is omitted, the 
purchaser may fairly ask a larger astronomical equipment; for its money value—compared 
with the latter—is about as 2 to 1. Extra attachments, usually at additional expense, 
may be had,—such as a diagonal eyepiece for viewing objects too near the zenith for 
convenient observation, and a “‘Herschel’”’ eyepiece for reducing the light and heat of the 
Sun to the eye. The latter is discussed in the chapter onthe Sun. The diagonal eyepiece 
makes the finding of objects more difficult, and it deprives the observer of the sense of 
direct vision. Many find such an attachment of great convenience, however, in viewing 
objects that are too high up for comfortable study with the ordinary equipment. The 
attachment is ‘‘popular,’’ though its cost is high in proportion to its actual working value. 
The diagonal eyepiece is shown on Model D, but it may also be obtained with practically 
all telescopes over two inches in aperture. On Model D and also on Model C is shown a 
‘‘finder,’’ a miniature telescope placed near the eye-end of the larger instrument. With its 
low-power eyepiece it affords a very large field of view. This is divided by two cross wires 
which by their intersection mark the centre of the field. The finder is so adjusted that 
when an object is brought to the centre of the field of view in the finder, it will be found 
at the centre of the field in the telescope proper, the two centres being coincident. This 
attachment is extremely desirable on instruments over three inches in aperture.  Tele- 
scopes of three inches and under do not needit. In the finding of objects, as has been already 
suggested, a low-power eyepiece may be used on the telescope itself, and, when the object 
is found, a higher power—if desired—may be substituted. 

14. First impressions are sometimes disappointing. The distance of the stars is so 
great, see p. 9, that the facts transcend all our ordinary standards of comparison. When 
we are told in one sentence that a celestial object is at least 1000 times larger than our 
Sun, it seems wholly absurd to learn in the next sentence that though we may use upon it a 
magnifying power of 100 diameters the telescope can show it to us only as a brilliant 
point of light. Let us suppose, however, that we were able to use a telescope magni- 
fying not 100 but 10,000 diameters. As such a telescope—even if its construction were 


Instruments of Observation 113 


possible—would magnify all the conditions of atmospheric obscurity or disturbance (as 
well as the star) no one could use it. But on the assumption that we could use it, what 
would it doforus? It would bring a star that might be 10 million million miles from us to 
an apparent distance of 1000 million miles. That is not very near! But there is no star 
so near as 10 million million miles. The very nearest is 4.3 light-years, or 25,000,000 millions 
of miles away; and no star so near as that can be seen from the latitudes of Europe or 
North America. Most of the stars are at far greater distances. As we bear these facts 
in mind, we need not be surprised if the telescope does not make any of the fixed stars 
assume the proportions of a tea-cup. In the case of the objects of our solar system—the 
Sun, the moon, the planets—an apparent enlargement of the image may be had. But 
there are many who find disappointment even here. Says Webb: “In viewing Jupiter in 
opposition with a power of 100, they will not believe that he appears between two and 
three times as large as the moon to the naked eye; yet such is demonstrably the case. 
There may be various causes for this illusion; —want of practice, of sky-room, so to speak, 
of a standard of comparison. A similar disappointment is frequently felt in the first 
impression of very large buildings; St. Peter’s at Rome is a well-known instance. If an 
obstinate doubt remains, it may be dissipated forever when a large planet is near enough 
to the moon to admit of both being viewed at once—the planet through the telescope, 
the moon with the naked eye.’’* 

15. A telescope equatorially mounted, having hour-circles but with no sidereal clock, 
may be directed to an object invisible to the naked eye by the following method. Note 
and record the difference in Right Ascension between the required object and some known 
object that may be readily recognized. (The beginner should remember, in calculating 
the difference in R. A. between two objects, that if this difference is greater than 12 hours 
the number 24 must here be added to the smaller R. A. before subtracting.) We proceed 
on the assumption that the object sought is toward the south. If the R. A. of the object 
sought be greater than that of the known object the former will be farther east; if the R. A. 
of the object sought be smaller, that object will be the farther west. Using your eye- 
piece of lowest power, direct the telescope to the known object, bring it to centre of field, 
and read the hour-circle. Now move it east or west, as need may require, until the index 
of the hour-circle has moved through a distance equivalent to the difference in the Right 
Ascensions. Now set the Declination circle, and the required object will be found within 
the field. Gibson wisely suggests that the known object be selected, if possible, on the 
same side of the meridian as the object sought. 

16. Telescopes variously mounted and fitted with adequate eyepieces may be had 
in the United States at the following retail prices. These prices are not to be taken as 
from the catalogue of any particular manufacturer. They are to be regarded as rough 
approximations, here introduced merely as a general guide to the purchaser. 

Telescopes of from 2 inches to 214 inches in aperture may be had at from $60 to $85, 
according to quality and type of mounting. There is usually not much difference in cost 
between a 2-inch and a 214-inch, and—other things being equal—the 214-inch is, of 
course, to be preferred. 

The same consideration applies to telescopes of 214 to 234 inches in aperture. These 
may be had at from $65 to $120, according to quality and type of mounting. Thesimple 
mountings cost less, and are usually efficient enough to meet the needs of the average 
observer. 


* Celestial Objects for Common Telescopes, T. W. Webb, M.A., F.R.A.S., vol. i., p. 16, ed. of 1907; Longmans, 
Green & Co., New York and London. 


114 Ll Beginner’s StarzBook 


Telescopes of 3 inches in aperture fitted with one terrestrial and at least two astro- 
nomical eyepieces can be had at from $75 to $170. Here again the simple ‘“‘alt-azimuth”’ 
mounting is quite adequate for all ordinary purposes. 

The prices of telescopes over 3 inches in aperture I do not attempt even to suggest— 
the variety is so great and the range of values is so large. If one desires, one can put as 
much as a thousand dollars into a 5-‘nch portable telescope. 

There are also instruments on the market at prices lower than any here quoted. With- 
out judging them, I have preferred to speak only of values that are personally known to 
me. Teachers and all who are on the purchasing committees of schools and colleges will 
take satisfaction in learning that the high customs tariff on telescopes of foreign manufac- 
ture is not applicable to instruments purchased for the use of educational institutions. 
Deductions, therefore, from the prices above quoted—ranging from 20 to 35 per cent.— 
are not infrequently made. The transaction, however, must represent a direct importa- 
tion, must be in the name, and for the use of, the institution, and instruments thus imported 
must not be for sale. 

17. <A few final notes are here thrown together.—In using the Key-Maps for the 
telescope, the beginner should first read the accompanying notes under the Night-Chart 
on the pages opposite.—Always remember, in using any of the Key-Maps, to begin as 
near as may be feasible at the centre cf the map, working from the centre outward.— 
While the telescopic objects are classified roughly for (I) the Opera-Glass and the Field- 
Glass, (II) the Two-inch Telescope, and (III) the Three-inch Telescope, these divisions 
are necessarily somewhat arbitrary. An object listed for a 2-inch, may be seen to even 
better advantage in a 214, or 2%, or 234, or 3-inch; and some of the objects classified for 
the 3-inch may be well observed, under good atmospheric conditions, through smaller 
telescopes,—especially if the observer has had the advantage of a little experience. 
Those, moreover, who possess 4-inch or even 6-inch telescopes will find that the selected 
objects are not less interesting or less beautiful because adapted to smaller apertures,— 
any more than a drop of water is less interesting as we increase the range or refinement of 
the microscope. Should the observer wish to work in entire independence of the classi- 
fications under the Key-Maps, he has only to turn, in the Observer’s Catalogue, to the 
constellation desired, where the best maps are indicated and all the important objects 
noted.—The beginner is reminded that in viewing the fu// moon there are certain advan- 
tages in using the terrestrial rather than the astronomical eyepiece; the additional or 
erecting lenses serve to reduce the excessive brilliancy of the object. See pp. 70, 71.— 
Teachers who may wish information as to the adaptation of this book to their educa- 
tional work (either alone or for supplementary use) may obtain a special circular on 
epplication to the author, in care of the publishers. 


“Herbert Spencer has somewhere reminded us that the crowbar is but an extra lever added to the levers of which 
the arm is already composed, and the telescope but adds a new set of lenses to those which already exist in the eye. 
In a very deep sense all human science is but the increment of the power of the eye, and all human art is the 
increment of the power of the hand. Vision and manipulation,—these, in their countless indirect and transfigured 
forms, are the two codperating factors in all intellectual progress.’— JOHN FIsKE; The Destiny of Man; Chapter VII, 


NEBULA IN SAGITTARIUS, KNOWN AS MESSIER 8 


rom a photograph taken at the Yerkes Observatory 





UI. HH Brief Observer's Catalogue of Telescopic Objects 


.. This Catalogue is limited to objects of the Stellar World; for the objects of the Solar System, see Chapter V. 


Explanatory. The objects discussed under 
the Night-Charts and Key-Maps, pp. 38 to 61, 
are there given reference numbers in brackets 
[ |]. These refer to corresponding numbers 
in this catalogue. The catalogue will thus be 
found to contain a good deal of material for 
which there was not space under the maps. 
Some of this the beginner may not at first 
want, but there will be an increasing desire for 
additional facts as interest and knowledge grow. 
Here are given, also, the positions of the stars 
by Right Ascension and Declination—for the 
use of those who may possess instruments 
with hour-circles (see p. 107) and for all who 
may desire to find the places of the stars, in 
star atlases or in charts of the celestial sphere, 
with more precision than is possible in a mere 
general reference to the constellation. See 
note 14 on page 32. 

While the telescopic objects are chiefly noted 
under the Key-Maps on the right-hand pages, 
39 to 61, the beginner should not fail to read 
also, in each case, the matter under the corre- 
sponding Night-Chart. A few telescopic ob- 
jects not noted under the Key-Maps areincluded 
in this Catalogue. 

Here also will be found indicated the exact 
magnitudes of the stars. These are given 
according to the Revised Harvard Photometry, 
1908. In some cases the magnitudes of the 
smaller components of the double stars are 
not given in that list. In such instances they 
are chiefly taken from the Sternverzeichniss of 
Ambronn, Gottingen, 1907, as stated in the 
preface to this book. From that compilation 
I have also taken the estimates of star colors, 
and where these are omitted in the Ambronn 
list, I have fallen back on the impressions of 
Webb or Smyth, except where very subtle 
distinctions of color have seemed overdrawn. 
Small instruments do not show, as a rule, any 
but the clearer and sharper color-contrasts; 
but much depends, of course, upon the quality 
and construction of the telescope and on the 
local conditions of light and air. More still 
depends on the personal equation of the obser- 
ver,—some eyes are color-blind; some, if the 
term may be coined, are color-wild, seeing 
hues and tints ‘‘that never were on sea or 


land.’’ Avoiding both extremes, the beginner 
will find much of charm and pleasure in the 
study of color-contrasts. 

Here also are given the distances between 
the components of double or multiple stars, 
as measured in seconds of are. Thus the 
observer may secure a general idea as to 
the distance at which he may expect to find 
the members of a composite system. A still 
greater help in detecting faint companion 
stars may be obtained from a rough knowledge 
of ‘‘the position angle.’”” The beginner will 
do well, at the very first, to confine his obser- 
vation to double stars in which the compo- 
nents are rather widely placed and so bright 
as to make a knowledge of the position angle 
unnecessary. To some minds the understand- 
ing of position angle measures is very easy; to 
others it is difficult. The chief point to be 
remembered is that the amateur may find 
much pleasure in the observation of such stars 
without going into the question at all. As the 
observer comes to take up the subject, a few 
words of explanation may be useful. 





POSITION ANGLE OF DOUBLE STAR 
As shown in Astronomical Telescope, Image Inverted 


The angle is reckoned from north (below) at zero; through east (90°); 
and south, 180°; round through 270°, west; to completion 
of circle at 360° 


First, let us assume that the angle is measured 
when the star, as we face south, is on the me- 
ridian;—that is, at the moment when the star 
culminates or reaches its highest point in its 
course from east to west. Let us thus first 
secure our mental picture of the position angle 
as an angle measured not at the moment 
when the star rises or sets or is east or west, 
but at its upper culmination. 


116 


fin Observer’s Catalogue 


Of the two lines, therefore, which meet at a 
point and form the position angle, one is the 
line from north to south running through the 
brighter component of the culminating star 
(as the line 0 to 180 in this diagram), the other 
line is that connecting the two components of 
the star, Ato B. This line is always drawn in 
imagination from the brighter to the fainter 
component; and the angle is reckoned, as in 
the field of an astronomical telescope, from 
below at zero around to B. In our illustration, 
for example, the position angle of the double 
star A-B is 210 degrees. 

We learn in this way the direction in which to 
look for the fainter component of a double 
star. Delta (6) in Corvus, for example, has 
almost the same position angle as that shown 
in our diagram. In the sketch given on page 
26, Delta (6) is the brighter of the two stars 
at the upper left-hand corner. The smaller 
star there shown should not be confused with 
the telescopic companion. When Corvus is 
due south or approximately south, see position 
B, page 26, the small component will be found 
upward and to the left,—about as in our dia- 
gram here. As Delta (0) rises—or when the 
constellation, p. 26, is at position A—the posi- 
tion angle is of course unchanged but the appar- 
ent direction which it indicates will vary with 
the position of the group. At A, therefore, 
the telescopic companion will appear lower 
down and toward the left. As the star swings 
westward to position C, page 26, the small 
companion will appear upward and to the 
right. 

Turn now to page 25, and note the case of 
Delta (6) in Orion, the uppermost of the three 
stars running diagonally through the square. 
The position angle of this star is 0°. It might 
also be written 360°, as we may see from 
our diagram, p. 116. This means, of course, 
that when Orion is at position B, due south, 
the fainter component is directly below the 
brighter. Wemay see, however, from the illus- 
tration on page 25, that when Orion is east- 
ward, at position A, the small companion to 
Delta (6) must appear below, but to the right; 
and that when Orion is at position C, it must 
appear below and to the left. For the appar- 
ent direction of the companion wi!l naturally 
change, as in the case already cited, with the 
changing “slant’’ or inclination of the group. 
This will become quite clear with a little 
actual experience in observation. 

In studying our diagram of a position angle, 
the reader should note that it is drawn for use 
as the observer faces south. In facing north- 
ward the beginner should remember that since 
the zero-point must always be toward the north 
pole, the top and bottom of the diagram will 
be reversed for stars culminating between the 
pole and the zenith. For the northward stars 


Lr 


when below the pole, the diagram requires no 
inversion. 

References will sometimes be found in this 
catalogue to double-stars as ‘‘doubles,”’ to a 
star with three components as a “‘triple,’’ etc. 
In many cases a double-star is known to repre- 
sent a system in which both the components 
are in revolution about a common centre of 
gravity. Such doubles are called ‘* Binaries.” 
All binaries are double, but all doubles are not 
necessarily binaries. References will also be 
found to ‘‘spectroscopic”’ binaries. These are 
binary systems in which the components are 
so near that their division or separation can 
be detected only by the spectroscope—being 
too close together for the telescope to show 
them as separate objects. A full discussion 
of the spectroscope and of its marvellous 
revelations lies outside the plan of this book; 
the reader may find such information in some 
of the volumes noted on page 144. Here it 
may only be crudely said that these results 
are obtained in the case of each star by the 
study of the composition and action of its 
light. Investigations also conducted with the 
spectroscope have told us that the stars have 
besides their ‘‘apparent’’ motions (such, for 
example, as the motion from east to west 
caused by the revolution of the earth) and 
their ‘‘ proper motions’’ in space, see page 139, 
definite individual motions in the line of sight, 
motions directly toward, or directly away 
from, our solar system. When the reader 
finds, therefore, in this catalogue that a par- 
ticular star is said to be approaching the earth 
or receding from the earth at the rate of 10 or 
I5 miles a second, it should be understood that 
the instrument which brings us such results 
is not the telescope but the spectroscope. 
The facts as to the actual movements of the 
stars are so striking that they might awaken 
our alarm but for the consideration that the 
stars are almost inconceivably far away, so 
far indeed that these movements may possess 
for us an element of interest but not the least 
element of anxiety. The same consideration 
should be borne in mind in thinking of the 
“proper motions”’ of the stars; p. 138. For the 
stars are not really at rest. They seem so to be, 
because of their great distance from us. But 
most of them, like the Sun itself—our own star, 
—are moving through space at high velocities. 

References, therefore, will also be given here 
to the distance from us of certain of the stars, 
and a table dealing more fully with the data 
will be found on page 139. Theinstrument by 
which the most trustworthy of these results 
have thus far been obtained is a modification 
of the telescope called the heliometer. Other 
methods, some of them employing photo- 
graphy, for the determination of star distances 
are now being matured. 


118 


The first association of the stars into con- 
stellations or star-groups is prehistoric. Some 
of the most familiar—such as Orion, the 
Pleiades, the Hyades, as well as the stars 
Sirius and Arcturus—were known to Hesiod 
(c. 800 B.c.) and they appear in Hesiod as 
already well known and long established. 
The earliest formal lists are those of Eudoxus 
and Aratus (c. 400 and c. 270 B. c.) though 
it is to Ptolemy (150 A. D.) that we owe the 
full list of 48 constellations familiar to the 
ancient world. Of these, the most important 
are those of the Zodiac; see p. 80; namely, 
Aries, Taurus, Gemini, Cancer, Leo, Virgo, 
Libra, Scorpius, Sagittarius, Capricornus, Aqua- 
rius, and Pisces. Those north of the Zodiac 
in Ptolemy’s list were: Ursa Major, Ursa 
Minor, Draco, Cepheus, Bootes, Corona Bo- 
realis, Hercules, Lyra, Cygnus, Cassiopeia, 
Perseus, Auriga, Ophiuchus, Serpens, Sagitta, 
Aquila, Delphinus, Equuleus, Pegasus, An- 
dromeda, Triangulum; and south of the Zodiac 
as follows: Cetus, Orion, Eridanus, Lepus, 
Canis Major, Canis Minor, Argo, Hydra, 
Crater, Corvus, Centaurus, Lupus, Ara, Corona 
Austrina, and Piscis Austrinus. The myths or 
legends connected with the more important 
of these are given in this Observer’s Cata- 
logue in their Greek forms,—though the Greek 
version is often but the recasting of an earlier 
myth. 

Abbreviations. Theobjects listed are grouped 
by their constellations, in alphabetical order. 
First, comes the name of the constellation. 
Then follow page references to the Key-Maps in 
which it is to be found for observation in the 
evening sky. Then come references to N. H. 
or S. H. (northern hemisphere or southern 
hemisphere), indicating the mean Right Ascen- 
sion (R. A.) and Declination (D.) of the group, 
for reference to the hemispherical maps at the 
close of the volume. As the map of the north- 
ern hemisphere contains a large overlap of 
the southern sky, the abbreviation N. H. at 
this point does not necessarily mean that the 
object is north of the equator but merely that 
reference is made to the first (and larger) of 
the two maps. See note 14, p. 32. The 
celestial equator should not be confused with 
the ecliptic; it will be found to run through 
Hydra, Orion, Aquila, Serpens, etc. The 
letters S. H. refer to the map of the southern 
hemisphere, the smaller of the maps at the 
book’s close. 

In writing of the double or multiple stars, 
the letters A, B, C, etc., usually refer to the 
components in order of brightness. The word 
““distance”’ is used for the distance between 
such components; and the letter p. for the 
position angle. The abbreviation Jag. refers 
to the magnitudes of the stars;— not their 
physical size or their actual luminosity, but 


H Beginner’s StarzBook 


their relative brightness as seen with the 
unaided eye or with the telescope. In the case 
of double stars, the position assigned (in R.A. 
and D.) is for the brighter component; and for 
the year 1900. Following recent usage, the 
fractional parts of a minute (in noting R. A.) 
are here expressed not in seconds but in 
decimals. One minute and thirty seconds, for 
example =1.5 m. 


A’-cher-nar, see [175]. 
Al-déb’-a-ran, see [381]. 
Al-tair’, see [21]. 


1.—An-drém’-e-da (Maps pp. 55, 43, 61, 41. 
N.H., R. A. Ih., D.+40°). A fine constella- 
tion lying between Perseus and Pegasus, its 
brighter stars forming an almost straight line. 
According to the Greek myth, Andromeda 
was the beautiful daughter of Cepheus, king 
of the ancient Athiopia, and his queen, 
Cassiopeia. The queen in the pride of her 
own beauty sat one day enthroned by the 
sea, plaiting ‘‘ambrosial tresses.’’ There, in 
the hearing of the sea-nymphs, she boasted 
that she was fairer than they. Deeply enraged 
they succeeded in having a sea-monster sent 
to ravage the coasts of the kingdom. Ap- 
pealing for help, Cepheus and his queen were 
informed that the penalty could be averted 
only by exposing their daughter, Andromeda, 
as a prey to the monster. She was chained 
to a great rock by the sea to appease him. 
There she was seen by Perseus, returning from 
his victory over the Gorgon. The head of 
Medusa, which turned all who beheld it to 
stone, he bore in his hand. Calling to An- 
dromeda and bidding her to avert her face lest 
she perish also, he turned the sea-monster into 
a huge rock. Then cleaving with his sword 
the chains which bound the wrists of the maid, 
he bore her away as his bride. At death they 
were placed with Cepheus and Cassiopeia 
among the stars. The story is finely told by 
Charles Kingsley in his Greek Heroes. A 
later legend finds in Cetus, the Whale [110], 
the Monster of this older myth; and in Pegasus, 
the Winged Horse [301], the steed on which 
Perseus bore Andromeda away. 
2.—The famous nebula, M 31, isnot conspicuous 
in small instruments, but of great interest. 
R.A. o h. 37.2 m., D.+40° 44%, Aneilliietra= 
tion of the nebula will be found on p. 20. 
The estimate of its dimensions as given on p. 21 
is based on an assumed parallax of 0o”.o1 
(see Introd. to Astronomy, F. R. Moulton; 
New York; edition 1910, p. 541), and is prob- 
ably an understatement rather than an over- 
statement. The actual form of the nebula 
is probably less oval than shown in the engrav- 
ing. Some observers regard the oval shape 


Ein Observer’s Catalogue 


as wholly due to the way in which the object 
is tilted to the line of sight, but that its form 
is strictly circular is highly doubtful. Its 
appearance in a small instrument is somewhat 
disappointing. The striking and _ beautiful 
impression given by the camera is due not 
only to the efficiency of the telescope em- 
ployed but to the long exposure of the photo- 
graphic plate. This is the largest of the spiral 
nebule. The great nebula of Orion [294] is 
quite as large, if not larger, but irregular in 
ferm. 

3.—Gamma (vy) is a double star, one of the 
most beautiful of telescopic objects. It forms 
a right-angled triangle with the stars Beta (/) 
and Alpha (@) of Perseus; or it may be found 
by running an imaginary line from Polaris to 
Epsilon (€) in Cassiopeia and continuing it an 
equal distance. Mag. of components, 2.3 and 
5; A orange, B emerald; distance = 10”; p. = 63°, 
Pere s7.6 m.; D.+41° 51’. Bis also a 
double in a large telescope. The Arabic name 
for Gamma (y) is Alamak. The star is ap- 
proaching the earth at the rate of 6.84 miles a 
second or 410 miles a minute. See Table, p 
139. 
4.—Pi (7), a double star, mag. of components, 
4.5 and 9; A white, B blue; distance = 36”; p 
teagan On, 31.5 m.; D:-+33° 10’. It is 
interesting to note that this star is receding 
from the earth at the same rate of motion at 
which Gamma (/) is approaching, 6.84 miles a 
second; see above. 

5.—The little star marked 56 is an easy double; 
mag. of components, 6 and 5.8; both yellow; 
distance = 181”.6; p.=301°; R. A. Ih. 50.2 m.; 
D.+36° 46’. 


An’-ser, see Vulpecula [425]. 
Ant-a’-res, see [351]. 
An-ti’-no-us, see Aquila [20]. 


1o.—Ant’-lia, the Airpump. (Mapp. 49.S.H., 
hoes el), — 3207.) An unimportant 
southern constellation, too low in the sky in 
our latitudes for satisfactory observation; few 
objects of interest. 


15.—A-qua’-ri-us, the Water-Bearer (Maps pp. 
61,57, 41. R.A. XXII h.; D.—10°). A large 
constellation, important because lying in the 
Zodiac or pathway of the planets, see p. 80, 
but it is not conspicuous, having no stars 
greater than the third magnitude. 
16.—The globular cluster marked M 2 is not 
brilliant. Located by imaginary line from 
Zeta (€) in Capricornus to Beta (#) in Aquarius, 
and slightly continued. R. A. XXI h. 28 m.; 
DD. —.1° 16’. 
17.—The star Zeta (€), at the centre of the 
Y-shaped figure marking the mouth of the 
‘water-jar,” isa strikingly interesting double, 


119 


the components being of almost the same mag- 
nitude. Mag. of components, 4.4 and 4. 0; ; colors, 
both white; distance = ot ; D.= 217. Ros 
XX1h.23.7 mm. D7— 0° 32": 

18.—The star Psi (*b’) is an easy double even in 
a 2-inch instrument. Mag. of components, 4.5 
and 8.5; A yellow, B blue; distance =49”; p.= 
BI RN Le 007m. = 0 0, 


20.—A’-quil-a, the Eagle (Maps pp. 57, 61, 53. 
ING DR exes 20 Tee tse) ne Stats 
of Antinotis are now included in Aquila. As 
this constellation lies in the Milky Way, it 
presents rich fields for all low-power instru- 
ments, though containing few easy doubles. 
21.—Altair; a fine first-magnitude star, forming 
with Beta (7) and Gamma (y) one of the clear- 
est landmarks of the summer sky. R. A. XIX h. 
45.9 m; D. + 8° 36’. I have called the linear 
figure formed by Alpha (@), Gamma (vy), and 
Beta (f) the “shaft of Altair.” Altair, next 
to Sirius and Pro’cyon, is the nearest first mag. 
star visible from northern latitudes, being at a 
“‘light-distance”’ of 14 years; see p.9. Altair’s 
annual proper motion is quite sensible, being 
0”.65. It is yellowish white in color;—of the 
same general type as Sirius. It is approaching 
the earth at a velocity of over 1200 miles a 
minute. 

22.—Very near to Lambda (A) is a small double, 
not charted but easily found; marked as 75 in 
some maps; mag. of components, 5.5 and 7.5; 
A white, B lilac; distance = 34” 2 ue = 206°.6; 
R. A. XVII h. 59.7 m.; D.— 4° 

23.—A rich cluster marked MALT R ‘A. XVIII 
h. 45.8 m.; D.— 6° 24’, 


Arc-ti’-rus, see [41]. 


25.—Ar’go Na’-vis, the Ship Argo. A large 
constellation, most of which is too far south 
for satisfactory observation in our latitudes. 
Some stars of Puppis appear low down in 
Maps pp. 45, 49; but for the whole constella- 
tion.see of Hs, ReAv LX Bh. Di—55 2 Some- 
times divided into four parts—Puppis, the stern; 
Vela, the sails; Carina, the keel; and Pyxis, the 
compass. 

26.—The cluster marked M 46 is sometimes 
listed -as"1564,"0r/ 2437.) 16 1s not difficult, 
forming an interesting object for small instru- 
Aleit Gem ts we Ve Ve oS 72st) Aces 
27.—Can-d’-pus, the leading star of this con- 
stellation, the Alpha (a) of Argo (more specifi- 
cally of Carina) is second only to Sirius [66] 
in brilliancy, but as it is very much more 
remote, being at a distance of, at least, three 
hundred light-years, it is probably many thou- 
sands of times greater in mass. It is a star of 
the same type as Procyon; though enormously 
larger in size. It has an annual proper motion 
of o”.02 and a motion of 12 miles a second away 
from our system. 


[20 


30.—A’-ries, the Ram (Maps pp. 61, 41, 55, 45, 
ASW ING Hi RaeAGSI eh 0 tise als oe 
important constellation, lying in the Zodiac or 
pathway of the planets; see p. 80. This con- 
stellation, as will be seen by reference to the 
N. H. map, covers a far wider area than the 
region marked out by its three most con- 
spicuous stars. According to one of the Greek 
myths, the mother of Phrixus and Helle gave to 
the former a ram having golden fleece. Fleeing 
from Hera, their step-mother, they reached the 
sea; and both attempting to cross on the ram’s 
back, Helle was drowned (hence the Hellespont). 
Phrixus, after his escape, sacrificed the ram, 
and dedicated the fleece to Zeus. The fleece 
was carried away by Jason; but Zeus per- 
petuated the memory of the ram by giving it 
a place among the stars. 

31.—Lambda (A), a fine double star, mag. of 
components, 5 and 8; A white, B blue; distance 
= 38055. 45, cel eau eles cA girl ee) eee? Saas 
32.—Gamma (y)—the Arabic name is Mesartim 
—is aneasy double star. It was discovered by 
Hooke in 1664; though it was not the first 
double star discovered, as is sometimes stated; 
see [401]. Mag. 4.7 and 4.8; A white, B pale 
gray; distance=8”.6; p.=360°; R. A. I h. 48 
inst 18648 

33.—The star 30 is also a double. It bears no 
symbol in the Key-Maps, but it will be found 
just to one side of a line from Alpha (a) to 
Beta (4), continued a little over twice that dis- 
tance. Mag. 6.6 and 7.4; A yellow, B gray; 
distance =3073) p.— 2727 aks ee lees Toate 
D.+24° 13’. 


35.—Au-ri’-ga; the Charioteer. (Maps pp. 59, 
47 AS ATs 30. ING ede ek eA Views Oni 
+ 42°.) This constellation, among the ancient 
Greeks, was connected with several myths. 
Among these may be mentioned the story that 
the group represents Erichthonius, sonof Athena 
and Hephestus, who was thus given a place 
among the stars because of his invention of 
the chariot. The name of the constellation 
appears in the Greek star lists of Eudoxus (4th 
century B.c.) and Aratus (3d century B.c.). 
36.—Ca-pel’la, the leading star of the constel- 
lation, is accompanied by three fainter stars 
forming to the eye a small acute triangle. 
These, Epsilon (€), Eta (7), Zeta (€), are called 
the Kids, Capella itself meaning, literally, 
the she-goat. The presence of “the kids’ 
will always serve to distinguish Capella, in a 
clear sky, from the other bright stars. The 
group is situated so far to the northward that 
in its revolution about the Pole it is carried 
below the horizon, in our latitudes, for only 
a short period of time and so is almost always 
in our skies. Capella is brilliantly yellow or 
golden in color, and so much larger than our 
Sun that whereas Capella shines to us as a 


H GBeginner’s StareBook 


first magnitude star, the Sun at the same dis- 
tance would appear as a star of only the fifth 
or sixth magnitude. Capella is a spectro- 
scopic binary with a period of 104 days; see p. 
117. *It is at a light-distance of 49 years; 
and is receding from our system at a velocity 
of 18.6 miles a second. R. A. V Biome 
+45°54’. Exact mag. 0.21. 

38.—The small star marked r4 is an easy double, 
Mag. 5.1 and 7.2; A yellow, B blue; distance = 
14”.5; p.=225°. R.A. V h. 80 meeDeease 
34’; the star is triple in large instruments. 


Bet’-el-geuze, see [291]. 


40.—Bo-6’-tes, the Herdsman. (Maps pp. 53, 
49, 43, 47, 55, 57. N. H., Roeser 
D. + 30°. A large and important constella- 
tion of the northern hemisphere, south of 
Ursa Major and west of Corona. The con- 
figuration of the Herdsman as it is usually 
suggested will be found in the text under the 
Night-Chart on p. 42. While not in the Zodiac, 
or pathway of the planets, Bodtes is among 
the first recorded constellations. 
41.—Arc-tii’-rus; a superb first-magnitude star, 
R. A. XIV h. 11.1 m.; D.--19gy2 alee 
Sirius, Vega, and Capella, Arcturus is the bright- 
est star visible from northern latitudes. Indeed 
it is rated in the Revised Harvard Photometry 
(1908) as of mag. 0.24,—nearly the same as 
Capella (0.21). The star is of a deep yellow 
color, possessing at times an almost reddish 
cast. Its motion in the line of sight (186.6 
miles a minute) is toward us, but this ve- 
locity, as compared with many of the stars, 
is not high. The proper motion (see p. 138) 
of Arcturus is, however, unique among our 
brighter stars, making it an object of sur- 
passing interest. This great star, at least 
1000 times the size of our sun in volume, is 
rushing through space at a velocity of nearly 
90 miles a second, or over 320,000 miles an 
hour. The direction, according to Newcomb, 
is southwest, or toward the constellation Virgo. 
We must remember, upon the other hand, 
that as Arcturus is so far distant from our 
system, light from the star requiring more 
than forty years in which to reach us, the high 
velocity of its motion has not altered its appar- 
ent position in the sky in 4000 years by much 
more than 25°, or 5 times the apparent 
diameter of the moon. No change in its 
position within a century could be detected 
except by the use of instruments of high pre- 
cision. The advanced student should bear 
in mind that the above statement is based 
not on the parallax for the star of 0”.03 for 
some time current, but on the corrected paral- 
lax of 0”.075; see p. 139. 

42.—Epsilon (é), a beautiful double star, but the 
beginner will find it difficult even with a three- 
inch instrument; mag. 5.1 and 2.7; A pale 


Zin Observer’s Catalogue 


p.=330"; R. 
Arabic name, 


orange, B green; distance =2”.7; 
A. XIV h. 40.6 m.; D.+27° 30’. 
Izar. 

43.—Delta (6), double star; mag. 3.6 and 8; A 
pale yellow, B light blue; distance = 105”; 
Geeoe isan. XV h. 11.5 m.; D:+33° 41’: 
43b.—Xi (&), double star; mag. 4.8 and 6.6; A 
yellow, B purple; distance=3”; p.=200°; R.A. 
Ooi 46.8 m.; D.+19° 31’. 

44.—Pi (7), double star; mag. 4.9 and 5.8; 
colors, both white; distance=7”; p.=100°; R. 
fee Vengo m.; D.+16° 51’. 

45.—Kappa (x), mag. 4.6 and 6.6; A white, B 
Pirsh Gistance=13"; p.=238°: R. A. XIV 
Peeeone )-- 52° 15'; not far from Eta (7) of 
the Great Dipper. 

46.—lota (z) mag. 5 and 7.5; A pale yellow, 
B white; distance=38”; p.=33°; R. A. XIV 
ee? Otol). -1-51° So’. 

47.-—Mu (“), mag. 4.5 and 6.7; both white; dis- 
Peice05 90.171 .6; R: A, XV h. 20.7 m.; 
D.+37° 44’. 


48.—Cam-el-o-par’-dus, the Giraffe (Maps, 
mueenorserms N. H., R. A. V h:; D.+ 70°). 
A large but dull and unimportant constella- 
tion near the Pole. 

49.—The star marked 19 H is an easy and pretty 


double. Mag. 5 and 8.5; A yellow, B blue; 
distance =16"; p.=10°; R. A. V h. 6.1 m.; D. 
ISNT 


50.—Can’-cer, the Crab (Maps pp. 45, 49, 39, 51. 
Ree tiie hb. 25°m.: D.+-20°). A small dull 
constellation, but of importance because lying 
in the Zodiac or pathway of the planets. 
52.—A fine cluster called Pre’-se-pe, or the 
Beehive. The stars of this famous cluster 
are not so numerous as in many other clusters, 
but of sufficient magnitude to make a beauti- 
ful object in a small instrument. Galileo 
counted 36 soon after the making of his first 
telescope; later observers have counted over 
B0gmme ne VIITh, 34.7 m.; D.+20°. 
53-—lota (4) is a fine double, small but not 
difficult; mag. 4.2 and 6.6; A faint orange, 
B blue; distence = 51" ma 307 Rha A VIL ih: 
40.6 m.; D.+29° 8’. 

54 —Zeta (eyois' 4 pr triple star; only 
2 components can be easily seen in small 
telescopes; mag. 5.6, 6, and 6. 3; AB yellow, 
C orange; distance (AB- —C) =o) Be pe 
Tet A. VIII fio Sets: D.+17 57°; One a 
the most remarkable scare stars. The 
orbit of A and B has been well determined; they 
revolve about each other at a distance of less 
than 1”, in a period of 60 years, and are accom- 
panied by a third star, C, which revolves about 
the centre of gravity of all, in an opposite direc- 
tion. From irregularities in the motion of C, 
it is concluded that it is a satellite of an in- 
visible body around which it revolves in 17} 


Ze 


years, describing an ellipse with a radius of 
about % of a second, and that the two together 
circle around A and B in 600 or 700 years.’’— 
Sir Robert Ball. 

55-—The cluster marked M 67 is composed of 
stars of mag. 9-I2.5, surrounded by brighter 
stars in the form of a half-circle. The whole 
looks like a nebula in a small instrument, but a 
larger telescope shows the stellar formation of 
the Srotips eke allt. 46m .e-12- 10% 
This cluster is listed in some atlases ast i712; 
or 2682. 


60.—Ca’-nés Ven-at’-i-ci, the Hunting Dogs. 
(Maps, all northern except pp. 39, 59, also pp. 
AGIs 2mm aa EL ers woSL Liebe, Loo a A 
small modern constellation, near handle of the 
Great Dipper, or Plough. 

61.—Double star marked 12; Alpha (@) in 
some atlases. An easy object for very small 
instruments. This star was named by Halley 
“Cor Caroli’ (the heart of Charles) in honor 
of the English monarch, Charles II. Mag. 
2.9 and 5.4; A white, B blue; distance =20 ; 
Di 227 gun LL h. Si deimes-387.52¢ 
62. ee star marked 15 forms a wide double, 
easily divided by an opera-glass; the companion 
star is registered as 17; mag. 6.2 and 6; distance 
200 ata 207 aA et elise S80 etic ye eps 
gis 

63.—The nebula M 51, listed sometimes as 
TOO2, Of 5104s 16 illustrated om: p.- is Dut, 111s 
beyond the range of sei instruments. RAS 
XIII h. 26 m.; D.1-47° 4 

64.—This cluster, et M Be (5272)) 1s nov 
so beautiful in structure as the preceding object, 
but is within range of small instruments. So 
seen, however, its appearance is nebulous, 
showing little brilliancy. R.A. XIII h. 38 m.; 
D.+28° 53’. 


65.—Ca’-nis Ma’-jor, the Great Dog. (Maps, 
OMAGH TAO He RAV LL 1. 20.5) 
A fine constellation, southeast of Orion. 

66.—Si’-rius, the Alpha (a) of this constellation, 
bluish white in color, is by far the brightest 
star in the heavens, being of magnitude —1.6, 
and having about 12 times the brilliancy of 
Aldebaran or about 13 times that of Pollux or 
Spica. Its intrinsic luminosity exceeds that 
of our Sun by 20 times. It is also the nearest 
of the stars visible to the unaided eye from 
the latitudes of Europe or N. America. It is at 
a light-distance of 8.7 years. The small star 
61 in Cygnus was for a long time considered 
nearer than Sirius, but this is now known to be 
an error. Sirius represents, according to the 
spectroscope, a type of stars less advanced in 
development than our Sun, but older than the 
“Orion’”’ stars;see [290]. Its proper motion is 
1”.32 a year, equivalent to 10.3 miles a second, 
or over 36,000 miles an hour. The distance of 


122 


the star is such, however, that—although it is 
relatively so near—it takes a century of time 
for it to move through a space on the celestial 
sphere equivalent to 77 the apparent diameter 
of the moon. Its radial velocity (its velocity 
in the line of sight) is 300 miles a minute in 
the direction of our solar system. As Sirius 
is the leading star of the constellation, the Great 
Dog, it is sometimes called the Dog Star, and 
the days, July 25 to Sept. 5, when Sirius rises 
at nearly the same time as the Sun, are called 
‘“‘the dog days.’’ And Homer’s “Dog” was 
the star Sirius, always conspicuous in the night 
skies of autumn and winter. 


‘‘The autumnal star, whose brilliant ray 
Shines eminent amid the depth of night, 
Whom men the dog-star of Orion call.”’ 


For Sirius was also frequently represented as 
the hunting dog of the Giant Hunter (see 
[290] ). Sirius has a faint companion star, 
invisible except in large instruments. R. A. 
VI h. 40.7 m.; D.—16° 35’. 





67.—Star-cluster M 41, a fine spectacle in 
small instruments. R. A. VI h. 41.8.m.; D.— 
Oagom 


68.—Double star, Mu (4), mag. 5.2 and 8.9; 
A yellow, (By eray;: distance =2".5> 1p.=340.; 
RAS Vien 515: 1 1355 eis star 
not included in Night Charts; but easily found 
by ref. to its Right Ascension and Declination 
in N. H. Map at close of book. 


70.—Ca’-nis Mi’-nor, the Little Dog. (Maps 
pp. 45, 41, AQ wee Nereis mera Lelio yal 
D.+7°.) A small but ancient consteilation, 
mane of Canis Major, and containing one 
first magnitude star. 

71.—Pr6’-cy-on, “the precursor of the Dog’’; 
or the star which precedes or goes before the 
Dog-Star, z.e. Sirius. Procyon is a star of the 
first magnitude and has, like Sirius, a faint 
companion. Like Sirius also it is one of the 
nearest of the brighter stars, being at a light- 
distance of Io years. In its general nature or 
type it is midway between Sirius and our Sun. 
It has a proper motion of 1”.25. It is approach- 
ing our system at the rate of I50 miles a minute. 
ee AN 34.1 m.; D.+5° 29’. 

72.—The little star marked 14 is a triple; mag. 
5.5, 7, and 8; A white, B bluish, C blue; A-B, 
distance = 76”, p.=66°; A—C, distance=112”, 
D = 15300 wR eA Lets 2 eke acto Oe 


Ca-n6’-pus, see [27]. 
Ca-pel’-la, see [36.] 


75.—Cap-ri-cor’-nus, the Sea-Goat. (Maps pp. 
57.0 Doe Neat ine Ne A. XX hessoun.: Die 718.8) 
A constellation of small stars, but important 
because lying in the Zodiac or pathway of the 
planets. 


76.—The star Alpha (@); name Giedi; a re- 


El Beginner’s StarzejBook 


markable object, comprising at least six com- 
ponents. The two larger can be seen by a keen 
eye, unaided, or by a poor eye with assistance 
of opera-glass. Each of these is a triple; the 
four larger stars of the group are as follows: 
a‘, mag. 3 and 9.5; a’, mag. 4 and 9; color of 
two chief stars, yellow; a*—a?, distance = 376".1 

oR: A: (of a) XX hb. 120i Da 


— —Beta (f/), an easy but pretty double; 
mag. 3.2 and 6.2; A orange, B blue; distance = 
205"; i= 267 RRA: Xen 15.4 m.; D.- 
15° 6’. Arabic name, Dabih. ke 
78.—Omicron (0) is also an easy double, 
though more difficult than the last; mag. 6.1 
and. 6. 6; A white, B bluish; distance=22"; p.= 
240; R. A. XX h, 24.2 m.; D.—18° 

79. =F (2), a double star; mag. 5.1 and 8.8; 
A pale yellow, B bluish; distance = pe 53 p= 
M6; RGA ex xh, 21.6 m.: D.—18° 32’. 

79b. —Rho (p), a close double star; mag. 5 and 
Sep white, B yellow; distance = 3"; p.= 
173°; R. A. XX h. 23.2 m.? Di is oer 
location, see N. H., at the position just in- 
dicated. 


Ca-ri’-na, see Argo Navis [25]. 


80.—Cas-sio-pé’-ia. (Maps, all northern, p. 39, 
etc:: N. H., R. A. I°h.-)DE-6O = eer a 
and interesting constellation of the northern 
sky, directly across the Pole from Ursa Major. 
In the mythical history of the group, Cassiopeia 
was the mother of Andromeda; see [1] in this 
Catalogue. 
81.—Alpha (@); a fine double, though the be- 
ginner may have difficulty just at first in detect- 
ing the smaller component. The primary star 
is variable, being 2.2 mag. at its brightest. 
Mag. of companion 9; A reddish, B blue; dis- 
tance=62”; p.=280°. R. Alj70 "ieeaeamee 
D.+55° 59’. Arabic name, Schedir. 
82.—The star Eta (7) is one of the most famous 
binaries. There is much difference among 
observers as to the colors. They are probably 
yellow and red, but the smaller star seems 
purple in small instruments. See p. 16. Mag. 
3.7 and .7.6; distance=5”".6; p.=223 meee 
O43 in ea aasl ae 
83.—Iota (2), a triple star; mag. 4.8, 7.1, and 
1; A yellow, B blue, C blue; A—-B, distance 
=2" 2, p.=254°; A-C, distancé=9 spe nro = 
R. A. II h: 20.8 m.; D.+66>957/ Sean 
telescope will usually show only two com- 
ponents. 


Cas’-tor, see [186]. 


9o.—Cen-tau’-rus, the Centaur. (Maps pp. 
49 and 53; and S. H., R. A. XTID he sGe 
A large and brilliant constellation, visible, for 
the most part, only from latitudes near or 
south of the equator, but some of its northern- 
most stars can be seen in our evening skies of 


Zin Observer’s Catalogue 


June and July. Centaurus has two first-mag. 
stars, Alpha (a) and Beta (#). The latter is not 
among the nearest of the very bright stars, its 
distance being 88 light-years; it has a small 
proper motion of 0”.04 per year. 

g1.—Alpha. (@) is the nearest of the fixed stars, 
being at a light-distance of only 4.3 years. 
It is also a binary, the two components com- 
pleting their period of revolution in a little 
over 81 years. The brighter component of the 
system, called a”, matches our Sun very nearly 
in size and in constitution. The proper motion 
of the pair is 3”.66; they are approaching us at 
a velocity of 13.7 miles a second. 


100.—Cé’-phe-us. (Maps, all northern; N.H., 
Poe) h.; D.+73°.) A northern: con- 
stellation, on the other side of the Pole from 
the Great Dipper. For the story of Cepheus, 
see Andromeda [1]. 

to1.—The star Delta (0) is variable in magni- 
tude; maximum, 3.7; minimum, 4.6; period 
5d. 8h. 47m. 39s. It is also an interesting 
and easy double for very small instruments. 
Mag. of smaller star, 7.5; A deep yellow, B 
plue sdistance—41’+p.=192°; R. A. XXII h. 
25.4 m.; D.+57° 54’. 

102.— Beta (),.a double star; mag. 3.3 and 
8; A white, B blue; distance=13”.5; p.=250 3 
feel he 27.4 m.: D.+70.7’. Arabic 
name, Alphirk. 

103.—The star Xi (&) is also an easy double, 
easier for a 2-inch telescope than the preceding. 
Mag. 4.4 and 6.5; colors, both bluish; distance 
=o spi= 205.; R. A. XXII h. 0.9 m.; D.+ 
bAnS 

104.—The star Mu (/) was called by Sir 
William Herschel a “‘garnet’’ star, because of 
the intensity of its red color. In order to 
appreciate its peculiar hue, some white star, 
like the Alpha (@) of Cepheus, should be com- 
pared with it at the time. R.A. XXIh. 40.4 
m.; D.+58° 10’. 


110.—Cé’-tus, the Whale. (Maps DD molseAT® 
Pee ie Ath, 35 m:; D.—10°.) A large 
constellation lying westward from Orion and 
south of Aries and Pisces; see [1]. 

111.—Alpha (a), a second mag. star, yellow, 
with a blue star of the 5.5 mag. in same field; 
use low power. Not a true double, but an 
anvetesuine object. R. A. II h. 57.1 m.;'D. 
+3° 42’. Arabic name, Menkab. 
112.—Gamma (y), a fine double star for a 3- 
inch telescope; mag. 3.7 and 6.2; A yellow, B 
blue; distance =2” ae DE= O00 Ree Ane) eh. 
S51 10% Ds-+-2° 

rae —Omicron a one of the most remarkable 
of the variable stars; R. A. II h. 14.3 m.; D. — 
mem2o.) Its name is Mira=the Wonderful. 
The variability of the star was discovered by 
Fabricius in 1596. ‘In 1779 Herschel saw the 


123 


star when it was nearly as bright as Aldebaran, 
while 4 years later it was not visibleeven through 
his telescope. This means that at maximum 
it was at least 10,000 times as bright as at 
miminum. Ordinarily its maximum is much 
below that observed by Herschel and its mini- 
mum considerably above. Three hun- 
dred years have only added to the mysteries 
associated with its behavior.’’—Moulton, Jn- 
trod. to Astronomy, p. 531. See, also, p. 14 of 
this volume. 

114,—Zeia (6) optical dbliy mas. 3:5 and o: 
distatice=105 -pa—AlewReene [eh A6/50m- 
D.—10° 50’.. Arabic name, Baten Kaitos. 
116.—Double star, marked 66; mag. 5.7 and 
7.8. A pale yellow, B blue; distance =16”.6; 
r= 2308 he Ae elee7 see So 


Co-lum’-ba; see [125]. 


120.—C6’-ma Beér-e-ni’-ces, Berenice’s Hair. 
(Maps, PP- 49, 43, 53, 55; N. H., R. A, XU 
be40rm: +24°.) A small but interesting 
group ly1 ing between Leo and Bodétes. It is in 
the nature “of a scattered cluster, not conspicu- 
ous to the naked eye but extremely pretty in 
opera-glass, in field-glass of large aperture, or 
in small telescope with low-power eyepiece. 
According to the ancient myth, Berenice— 
Queen of one of the Ptolemies of Egypt, 3d 
century B.c.—sacrificed her beautiful locks as 
a thank-offering for one of her husband’s 
victories. Her hair, when shorn, was entrusted 
for keeping to one of Egypt’s temples. From 
this it was stolen. The queen bitterly la- 
mented the loss, and blamed the keepers of the 
shrine. They assured her, however, that Jove 
had placed her locks, for greater honor, in the 
skies; and they pointed out to her among the 
stars those strands and braids of twinkling 
light which we now know as “‘ Coma Berenices.”’ 
A very beautiful nebula, numbered in some lists 
as H. V. 24 (in others as 3106); is illustrated 


on p. 15. Unfortunately, it is not impressive 
iIngsmallvinetriimentsamy haves Li hees Taam: 
Da 267432). 


121.—The cluster marked M 53, noted in some 
atlases as 3453 or 5024, is also not brilliant in a 
small telescope. R.A. XIIIh.8m.; D.+18° 42’. 


125.—Co-lum’-ba, the Dove. (Maps pp. 41, 
Ane Oop Ree Aee Valeecoura. +) Daa 7s a 
small constellation, located below Lepus and to 
the west of Canis Major. Its brightest star, 
Alpha (a), mag. 2.8, is called Phact. 


130.—C6-r6’na_ Bo-re-al’-is, the Northern 
Growin laps pads Os NaH, AV ods 
35 m.;D.+30°). A constellation lying between 
Bootes and Hercules, forming a crown or chap- 
let of small stars; very beautiful as a group. 
The brightest star, Alpha (@), mag. 2.3, is 
called Gemma, the Jewel [of the Crown]. 


124 


131.—The star Zeta (¢) is a pretty double; 
mag. 6 and 5;A white, B blue; distance =7".5; 
D-=3057 RAV eS Orme s)2owse 


135.—Cor’-vus, the Raven, or the Crow. (Maps 
DDO, 5300 Nl eee ee Onna 
18°.) A small but clearly marked constella- 
tion lying between Hydra and Virgo. The 
two upper stars of Corvus point toward Spica, 
the first-magnitude star of Virgo, and form an 
interesting special group, see p. 26. 

136.—The star Delta (0) is an easy but pretty 
double; mag. 3.1 and 8.4; A yellow, B purple; 
distance = 24953 pi 214 haere eo ae, 
m.; D.—15° 58’. Arabic name, Algorab. 


140.—Cra’-ter, the Cup. (Maps PP. 49, 45, 53: 
Nae Riemesarn: ra Nae, eS aky small 
constellation of small stars lying between 
Hydra and Corvus. The stars form the out- 
line of a chalice or cup. The group contains 
few objects of telescopic interest. 


143:— Crux, ther Gross, (S.9hla Rea eel lehe 
30 m.; D.—60°.) <A small constellation near 
the south celestial Pole, remarkable for the 
‘Southern Cross,’’ a strikingly beautiful figure 
formed by its four brightest stars, one of which, 
Alpha (4a), is of the first magnitude; see p. 140. 
This star is at a distance of 59 light-years, and 
has a proper motion of 0”.06. 


145.—Cyg’-nus, the Swan. (Maps pp. 39, 51, 
57. IN) He RASS he20m:; D.--46 )) elying 
within one of the most impressive sections of 
the Milky Way, Cygnus contains many objects 
of interest and beauty. The stars Alpha (a), 
Beta ((), Delta (6), Epsilon (€), and Gamma 
(v) form the figure of a cross, and the group is 
often called the ‘Northern Cross” as dis- 
tinguished from the ‘‘Southern Cross,’’ noted 
above. The stars of the northern group, while 
not so brilliant as those of the southern, form 
an even clearer figure of the cross, because of 
the presence of a star, Gamma (vy), near the 
intersection of the beams. One of the most 
beautiful nebule of the constellation is shown 
on p. 8; but it is unfortunately beyond the 
range of the average telescope. 

146.—The brightest star of the constellation, 
Alpha (@), or Dén’-eb, is a star of the first 
magnitude (1.33), though one of the most 
remote among all the bright stars of the sky. 
It seems far less brilliant to us than Sirius, but 
its distance from us is so much greater that 
Newcomb estimates its actual luminosity as 
exceeding that of our Sun by at least a thousand 
times. It is distant from us more than 400 
light-years; its parallax being imperceptible and 
its proper motion being also very small (see 
tables, pp. 138 and 139). In spite of its vast 
distance, we know from the spectroscope that it 


El Beginner’s StarzjBook 


is a star of the same general type as Sirius, 
although probably more advanced in develop- 
ment. R.A. XX h. 38 m.; D.+44° 
147.—The star marked Beta (4) is given the 
name Al-bi’-re-o. It is one of the finest doubles 
for small instruments; mag. 3.2 and o4i A 
orange, B blue; distance = 34” 33D. = 55977 
A. XIX h. 26.7 m.; D.+27° 45’. No physical 
connection has been detected; the star is prob- 
ably not a binary. 
148.—The star marked Omicron (0) has an- 
other quite near it, marked in many atlases 0?. 
They form an easy group for an opera-glass or 
field-glass. In a 2-inch or 3-inch telescope a 
companion to 0? will be seen, and in a 6-inch 
instrument there appears still another com- 
ponent. This star, however, is very small, be- 
ing rated as 11th or 12th magnitude. The 
three components visible in a small instrument 
are 0', mag. 5; 0?, mag. 4; and the brighter 
companion of 0?, mag. 7. A and C are blue in 
color; B, or 0?, orange; A—B, distance = 3377.8; 
D.== 323 7-7. A- Cc, distance = 106".8: Pp: Le ede 
ReATor Os XX h. 10.5 m.; Dike) 20% 
149.—The star marked 32 is listed in some 
atlases as a double. This is an error, due to 
confusion with one of the components of the 
preceding object. But it is in the same inter- 
esting low-power field. R.A. XX h. 12.4 m.; 
D.+47° 24’. 
150.—This small object, marked 61, is one of 
the most interesting doubles in the sky,—the 
first star whose distance from our sun was 
accurately measured. Bessel (1838) found a 
parallax of 0”.31, indicating a light-distance of 
103 years. This was later superseded in 
general estimation by Auwers’ parallax of 
o0”.56, indicating a light-distance of 5.8 years, 
and making the star the nearest in the northern 
hemisphere. Statements to this effect appear 
in many current volumes of astronomy. But 
it has recently been determined that Bessel’s 
original result was far nearer to the fact; the 
parallax of 0”.31I is now generally accepted. 
The light-distance of the star is thus 10.5 
years; it is not so near as Sirius, but one of the 
nearest in our sky. See the table of star- 
distances, p. 139. The magnitudes of the 
components are 5.6 and 6.3; both yellow in 
color; (1905) distance = 22” “55 P. = [27 eRe 
XX ho ziaime D328 are 
151.—This star, which we. mark Chi (7) is 
marked in some atlases as y?, and the next star, 
17, 1s then marked y*. The former star, which 
we mark simply y, has a distant companion, 
but it is chiefly remarkable as a long- period 
variable. For six months at a time it remains 
invisible to the unaided eye. Its ‘‘period”’ is 
406 days. In about 33 months it Ronee 
from its minimum brightness, mag. 13.5, to 
maximum. Its maximum, as in the case of the 
Omicron (0) of Cetus, is by no means uniform, 


Ein Observer’s Catalogue 125 


—ranging from mag. 6.5 to 4. Its color is a 
fine red except that its color-intensity decreases 
with its increasing brightness. R. A. XIX h. 
46.7 m.; D.+32° 40’. 

152.—The star marked 17, sometimes called 
x', is an easy double for small instruments; 
mag. 5 | and 8; A yellow, B blue; distance = 26"; 

fee ek. A. XIX h. 42.6 m.; D.+33° 30’. 

I nee —Mu (4) is a triple; two of the components 
being almost inseparable in a small instrument, 
and the third, and smaller, star more distant. 
Mag. 4.7, 6, and OW as white, B blue, C blue; 


A-B, distance=2”, p.=125°; A-C, distance = 
Pepeepe—o1 ; R: A. XXIh. 39.6 m.; D.+28° 
ee 


154.—The star cluster M 39 is well worth 


finding. Itisonaline from Beta (f) to Gamma 
(y), continued about 14° onwards. R.A. XXI 
h. 28 m.; D.+48° 9’. 

155.—Del-phi’-nus, the Dolphin. (Maps pp. 


Eeaigsio N.H., R.A. XX h.40m.;D.+12°.) 
A small but finely marked constellation lying 
south of Cygnus and east of Aquila. 
156.—The star Alpha (a) is a wide double; mag. 
Bean oss) dicstance=35": p.=278°; R. A. XX-h. 
Boe. -15. 34’. 

157.—The star Gamma (/) is of special inter- 
est and beauty in a small instrument. Mag. 
5.5 and 4.5; A yellow, B bluish-green; dis- 
Paige 12.274: R.A. XX h. 42 m.; D.+ 
15° 46’. 

Dén’-eb, see [146]. 


160.—Dra’-co, the Dragon. (Maps, all north- 
erm, PP. 39, Brome Nel ik eae Ve Ly 552.100. 
D.+70°.) 
161.—This star, Alpha (a), is chiefly interesting 
because of its former position—4000 years 
ago—as the Pole Star. . Its ancient name was 
Tha’-ban. The Pole is now near the star 
Polaris in Ursa Minor. See [406]. For expla- 
nations of such phenomena, see any one of the 
text-books on Astronomy wae on p. 145. 
R.A. XIV h. 1-7 ™.; D.+64° 
162.—Nu (Vv) is an easy Nes Beatie double, 
even for opera-glass and field-glass. Mag. of 
both components, 5; color, gray; distance = 
bne ae 313 R.A. XVII h, 30.2 m.; D.+ 
So lie 
163.—Omicron (0) is another double. Mag. 
4.8 and aE 6; A yellow, B lilac; distance = 32”; 
pe=340 : R. A. XVIIEh. 49.7 m.; D.+59° 16’. 
ea This efar, lota(2), is alsoa double though 
more difficult than the star just mentioned. 
Mag. 3.5 and 9; A orange, B yellow; distance = 
meee 50 “R.A. XV h. 22:7 m3 D.+ 
59° 10’. 
165.—Gamma (vy) may possibly require a 3} 
or 4 inch telescope for its satisfactory obser- 
vation, as the companion star is even smaller 
than in the preceding pair. Mag. 2.4 and 12; 


@istance 1244.7 p.—116 > R.A OVI by sa 
m.; D.+51° 30’. Arabic name, Etamin. 
166.—Delta (6) is also a wide double and the 
companion is less difficult. Mag. 3 and 9-53 
A, yellow, B red; seat rine on: o (ee eiy 9h 
Ree re eX Shien (2.5 tre Deo 


170.—Equi’-le-us, the Little Horse (see N. H., 
R. A. XXI h. 10 m.; D.+5°), a small unimpor- 
tant constellation lyi ing between Delphinus and 
Pegasus. See the map of the N. H. at the 
close of this volume, at R. A. just indicated. 


175.—E-rid’-a-nus, the River. (Maps pp. 41, 
Ailes INS Bake enaNal, Gey, eb | ates SAUL sera lep canes 
D.—25°.) A long line of stars starting near 
Rigel in Orion and flowing westward and south- 
ward toward Cetus and Fornax. Few telescopic 
objects of interest, but it contains one first- 
magnitude star, Alpha (a), or Achernar (A’- 
ker-nar), visible only in far southern latitudes. 
pee fablesspp. 130, 140. 

176.—This star marked w is sometimes classi- 
fied as 32. The contrast in the colors of the 
components is peculiarly fine. Mag. 5 and 6. 93 
A yellow, B blue; lary ies Vane © 
Rea. TIT he 49.3 m.; D.—3° 

177.—Gamma (y) is a good ane for a 3-inch, 
though the companion—not to be confused wi ith 
the small 6-mag. star in the same field—is 
rather small. Mag. 2.5 and 10; A yellow, B 
paleseray distance —51.6:71p.—=238 ~ kh, ALE 
Hs 44 mee 13548) Arabic name, Zau- 
rak or Alhena. 


F6’-mal-haut, see [331]. 


185.—Gém’-in-i, the Twins. (Maps pp. 45, 
ATO Ome N teria eee Vil Lets ae). 22 4) 
One of the most interesting and important of the 
constellations. The two brightest stars, Cas- 
tor and Pollux, even in prehistoric times, were 
suggestive of a pair—so near are they together 
and so conspicuous in brilliancy. Many have 
been the legends, even among savage peoples, in 
which these stars have been identified with 
heroic groups. But the most familiar to us is 
that which has given them the names of the 
warrior brothers, sons of Jupiter and Leda, 
whom Macaulay celebrates in his stirring poem, 
“The Battle of Lake Regillus.”’ 

186.—The star Castor, marked Alpha (qa) in 
all star maps, is a double star, a binary,—a 
fine object for a 2-inch or 3-inch telescope; 
mag. 2 and 2.9; colors, both greenish white; 
distance 6.4 Ds 225. a nw AV LL ih, 28-28re: 
D.+32° 6’. It is also interesting to know that 
both components are spectroscopic binaries 
(see table of spectroscopic binaries on p. 143), 
and that at a distance of 73” is another com- 
ponent, mag. 9, visible only in larger instru- 
ments. The parallax of Castor (0”.028) makes 
its distance about 116 light-years. Both of 


126 


the main components of Castor are ‘‘Sirian”’ 
stars, see [66. | 
187.—Beta (/) or Pollux is a multiple star of 
at least 6 components, most of them at con- 
siderable distance from the primary and too 
faint for easy observation. Three may be 
seen in a telescope of 3 to 3% inches. ae ae 
QO, and 9.5; A orange; A-F, distance = 242", 
75°; A-E, distance =219", D200 oie oS, a 
He 30.2 1m; Di 28 #16) (Pollux vist brenter 
than Castor, although assigned the letter Beta 
(f). It is nearer, also; its distance is 51 light- 
years. It has a yearly proper motion of 0”.62. 
In its physical constitution it exactly resem- 
bles Arcturus [41]. It is slowly receding from 
our system. 
188.—The fine star-cluster marked M 35— 
beautiful even in a good field-glass and visible 
in an opera-glass—is a fine object in a small 
telescope. Its existence, under good atmos- 
pheric conditions, can be detected with the 
unaided eye. R. oni aenay Bin) --24e 2s 
189.—Kappa (%), though not a large star, is an 
extremely pretty double in a 3-inch glass. 
Mag. 3.7 and 8; iA orange, B pale blue; distance 
Sev ap eaicy a 1h ‘VIL h. 38.4 m.; D.+24° 
a3 


a 
190.—Delta (0) is an easier double than the 
preceding. Mag. 3.7 and 8; A yellowish, B 
fed distante=—7"p.—210.* ReA. Vil hy i142 
m.; D.+22° 10’. Arabic name, Wesat. 
IQI —Epsilon (€) is also a double star. Mag. 
3.2 and 9.5; A white, B blue; distance = 110’ 6; 
Di= 04g Re sab hy 37.8 m.: D.+25° 14’. 
Arabic name, Mebsuta. 
192.—Lambda (A) is a double star, mag. 4, 
unmarked by any letter in Key-Maps, just 
below Delta (6) and Zeta (€) and forming a 
small triangle with them. It isa little difficult 
for any telescope smaller than a 3}-inch, but 
is worth trying with a 3-inch on a clear night. 
Mag. 3: 7 and 10; A white, B yellowish; distance 
10) 1230. . Re Ae ene [231m elo. 
se 
193.—Zeta (€) is itself a double star, and is an 
easy object even in a 2-inch instrument. Mag. 
of brighter star varies from 3.7 to 4.3; smaller 
component, about 7; A yellow, B blue; distance 
= 04 == 25 Ow VL aan Orage reo 
Arabic name, Mekbuda. 
194.—The small star Nu (v) is here inserted 
not only because it is a double, but because 
of its historic interest. It was near this star 
that Sir William Herschel discerned the ob- 
ject which he found to be an unknown planet, 
a discovery which—to human knowledge— 
doubled the diameter of the solarsystem. Ura- 
nus, as it came to be called, is over twice as far 
from the sun as Saturn, the remotest planet 
then known. The components of the little 
star Nu.(*) are mag. 4,and 8 distance =1127> 
22233077 Re Aw VliDe 24 ts) eet 20 wie 


¢ 


El Beginner’s StarzBook 


200.—Her’-cu-lés. (Maps pp. 53,47; 57, 595 
N. H., R. A: XVII h. 20 m.; Di-es30 ieee 
large and important constellation ee be- 
tween Lyra and Corona Borealis, and south of 
Ursa Major. The group is not easily recog- 
nized at first, but when once learned it becomes 
strikingly clear and interesting. The hero, as 
usually drawn, is supposed to be kneeling, his 
head at Alpha (@), shoulders at Beta (f) and 
Delta (5), belt at Zeta (€) and Epsilon (é); 
one knee at Rho (p) and one at Eta (7). In 
early lists, the constellation is often called the 
Kneeler. The easiest method for noting and 
identifying the group is indicated on p. 46. 
201.—Alpha (q@) is a double star of especial 
charm and beauty. As the larger component 
is variable in brilliancy, the star will be found 
easier to divide at some seasons than at others. 
It can be divided, however, by a 3-inch, and 
sometimes by a 2-inch. Mag. (about) 3.5 and 
5.4; A yellow, B blue; distance=4”.8; p.=113°; 
R. A. XVII h. 10.1 m.; D.+14 4oeArapic 
name, Ras Algethi. 

202.—Delta (0) is an easier double than the 
above, if the air be clear and the night moonless. 
Mag. 3.2 and 8; A greenish, B bluish; distance 
alm p.=195 ;R.A. XVII. 10.9 my eon 


OTe 

203.—Mu ();—Mag. 3.5 and 8; A yellow, 
B blue; distance =31".5; p. =245 4. ane 
i. 42:5)m Det oye 

204.—Rho (/) is a double, unusual in its color- 
ing, the components being white and green. 
Mag. 4.5 and 5.5; distance=47 meet a- 
R. A. XVII kh. 20.2 m.; Diba 
205.—This star, marked 95, is also peculiar in 
the coloring of its components, one being red 
and the other green. It is not a difficult 
object, even for a good 2-inch, but it is small 
and not easy for the beginner to find. Mag. 
5.1 and 5.2; distance=6"; p/=262 ase 
XVID-hY S7223m; eee oie 

206.—The star-cluster M 13 is one of the most 
remarkable in the sky, comprising over 5000 
stars. Sir Wm. Herschel’s estimate of 14,000, 
though naturally suggested by the splendor 
of the central mass, was probabiy too large. 
Halley, who discovered it in 1714, reported 
it as one of six ‘‘nebule,’’—all that were 
known in 1716. Before 50 years had passed, 
Messier had added nearly 100, and by 1830 
the three Herschels (Sir William, Sir John, 
and Caroline) added more than 3000, counting 
both nebulz and star-clusters. These were at 
first classified together,—for the nebulz were 
generally regarded as star-clusters too distant 
or faint for the stars to be resolved by the 
telescope. We now know that the two classes 
of objects are distinct in character, see p. 19. 
M 13 is visible even in a 2-inch telescope, 
though its real interest and splendor cannot 
easily be gathered from an instrument less than 


Hn Observer’s Catalogue 


Gxinchesein aperture. R, A. XVI h. 39.1 m.; 
D.+36° 39’. 

207.—The star-cluster marked M 92 lies almost 
on a line between Pi (z) in Hercules and Beta 
(8) in the head of Draco. Easily visible, but 
with the appearance of a nebula, in small in- 
struments. R.A. XVIIh. 14 m.; D.+43° 15’. 
208.—Gamma (vy), a double star; ‘mag, 3.8 and 
8; A white, B lilac; distance= 40" 55 P f—2A0e 
R. A. XVI h. 17.5m.; D.-- 19°. 23’. 
209.—Kappa (), shown onlyin N. H., s. west 
of Gamma (y). An easy double for very small 
instruments. Mag. 5.1 and 6.1; A yellow, 
femeddisn distance =31"*'p.=10°; R. A. XVI 
eee Ontse) -17° 109’. 


Hy’-a-des, see [383]. 


210.—Hy’-dra, the Water-Snake. (Maps pp. 
Pomoc, H.. R.A. XI h.s D:—17°.) A 
constellation extending through more than a 
fourth of the southern sky, long and winding in 
form but not broad. Head south of Cancer, 
lying between Leo and Canis Minor; the tail 
reaching to Scorpius. 

211.—Alpha (a) is sometimes called Cor 
Hydre, or the heart of Hydra; sometimes Al- 
phard, the Solitary—as it shines brightly in a 
region of faint stars. It is a double, but diffi- 
cult in anything less than a 33-inch. Mag. 
2 and 10; A orange, B green; distance = 281”.2; 
Deetse kA. LX h. 22.7 m.; D.—8° 14’. 
212.—Epsilon (é) is a multiple star of four com- 
ponents, but in a 3-inch or even in a 33-inch 
not more than two are likely to be seen. Mag. 
a5 and 6.8; A yellow, C blue; distance = 3" Gie8D 
aoe R. A. VIII h. 41.5 m.; D.+6° 47’. 


220.—-La-cer’-ta, the Lizard. (Maps, all north- 
ern, except pos47and 59.. N. Hi; R.A. XXII 
h. 19 m.; D.+45°.) A small, inconspicuous 
constellation of little importance. 

221.—The star marked § is a quadruple, but 
only two of the components are visible in 
instruments under 4 inches. Mag. 6, 6.5, 10, 
and 8.7; A white, B white, C greenish, D blue; 
A-B, distance = 22” 633 Ds = 186°: 182) a Paral NE Aol 
mites) 30. 7’. 


225.—Lé’o, the Lion. (Maps pp. 45, 49, 53; 
Somot elt. R.A. X h. 25 m.; D.+15°.) 
One of the noblest of the constellations; between 
Cancer and Virgo; specially marked by the 
figure of the ‘‘sickle’’ formed by the stars 
Alpha (a), Eta (7), Gamma (y), Zeta (€), Mu 
(4), and Epsilon (€). The constellation lies 
in the Zodiac,—or track of the planets; and as 
it occupies a large part of the sky, the constel- 
lation-outline is often obscured or confused by 
one of the ‘‘wanderers.”’ 

226.—Alpha (a) or Rég’-ii-lus, its brightest star, 
is a double, though rather difficult for a 3-inch. 
Mag. 1.8 and 7.6; A white, B purple; distance 


127 


= WWigk Oe =O eh hog Mm. .- 1227, 
Regulus is reckoned a_ first-magnitude star, 
although it is less than 4 as bright as Vega 
[261], and only 7s as bright as Sirius [66]. 
Its small parallax indicates a distance of more 
than 80 light-years. The spectroscope places 
it among the ‘“‘Orion”’ class of stars, for which 
see [290]. 

227.—Gamma (y) is one of the finest of all 
the double stars, and one of the most impres- 
sive binaries. Fortunately the distance be- 
tween the components seems to be increasing, 
so that it is becoming still more available for 
small instruments. Mag. 2.6 and 3.8; A 
orange, B yellow; distance=3”.6; p. = 117°; 
R. A. Xh. 14.5 m.; D.+20° 21’. Arabic name, 
Al Gieba. 

228.—Tau (7) is a double so easy as to be 
separable by a good field- glass; mag. 5.4 and 7 73 
distance = 90"; pr=a170 3 R.A. XI h. 22.8 m. 
Deesecar 

229.—Beta (f) or Deneb’-ola has a small neigh- 
bor star: too distant for real component; mag. 
2.2 and 7-. A. bluish, B red: distance = 1134”; ; 
Diao tiak Aa bai, sls 5 6 


235.—Lé’-o Mi-nor, the Little Lion, literally the 
Lesser Lion. (Maps pp. 39, 43, 45, 49, 5I. 
Nee Ae eh. 20mm. 1): -+-349.)) A small 
constellation of little importance, lying be- 
tween Leo and Ursa Major. 


240.—Lé’-pus, the Hare. (Maps pp. 41, 45. 
Na Hee R Ae Vieb32.t0. ),—20-). A: small 
constellation, just south of Orion. 

241.—Alpha (q@) is a little difficult for a 3-inch, 
but easy for anything larger—if the eye be 
carefully on the lookout for the dull color of 
the companion. Mag. 2.6 and 9; A yellow, B 
oTaye distance —36/- 9p. = 1507; RatA.. Vv .h. 
28. 3 m.; D.—17° 54’. Arabic name, Arneb. 
242.—Gamma (/) is a wide but lovely pair, so 
easy as to be separable even by a good opera- 
glass. Mag. 3.8 and 6.4; A yellow, B pale 
green; distance=95”; p.=350; R. A. V h 
AO.3 Me )-—22 1220/2 

244.—Beta (f), a rather difficult triple, except 
in instruments of 34 inches and over. Mag. as 
10, and 11; A-B, distance = 3”, p.=300°; A-C, 
distance =66”; Pe TAO wake: eo ve te BAvin ge. 
—20° 50’. Arabic name, Nihal. 


245.—Li’-bra, the Scales, or the Balances. 
ees PP- 53, 49s 57- N. if ReAT A Veh ad. 15 
Ds 135s) er Ausmall constellation lying in the 
Zodiac or track of the moon and planets; 
between Virgo and Scorpius. 
246.—Alpha (a) is a wide double, easily divided 
by field-glass or opera-glass; mag. 2.9 and 5. 3; 
A yellow, B gray; distance = 230” Ses D- =a144- 
RerAges Wend erm sl. —15.135.. Arabic 
name, Zuben el Genubi, the southern scale. 


128 


247.—Beta (8), not double in a small telescope, 
but the star is interesting because of its pale- 
green color, Mage 2275, Ka ee Ome 
D.—9° 1’.. Arabic name, Zuben el Chamali. 

248.—lota(z) is a double but not easy even in a 
3-inch. Mag. 5.5 and 9. 53 A yellow, B purple; 
distance = 57” Sng esi EO) 45. The smaller com- 
ponent is also double in a larger instrument. 
RAS XV he 6:5: i—10 425% 


250.—Li’-pus, the Wolf. (Maps pp. 52, 53. 
SCH ReAl XV he 2o-me D402 Per he 
reader should use the map of the S. H. fora 
view of the whole; the name not appearing in 
the smaller maps. <A _ constellation lying 
directly south of Scorpius. Few of its stars 
ever rise sufficiently high in Europe or the 
United States for satisfactory observation. 
251.—Xi (&) is an easy double, even in a 2- 
inch telescope. Mag. 5.4 and 5.7; distance= 
Tl 'p: =48- ReAYX Ve 505 1 De eo 
252.—Eta (7) is also a double, though not 
quite so easy as the preceding. Mag. 3.6 and 
7.6 distance ="15 m (2 1g lara wee Lge as 
iter ooere 


255.—Lynx, the Lynx. (Maps pp. 39, 43, 51. 
N.) Hi RAs VID he: Dias Je An ancon- 
spicuous constellation, of little importance, 
lying between Ursa Major and Gemini. 
256.—The star marked 7g is an easy and pretty 
triple. It is on a line from Polaris to Pollux, 
about 25° from the former, though the beginner 
will not find it readily. Mag. 6.5, 6, and 8; 
A white, B and C purple; A-—B, distance= 
143 Spe eA dt 21 5 r= aoe Re 
VII h. 14.7 m.; D.+55° 28’. 


260.—Ly’-ra, the Lyre. (Maps pp. 57, 59, 47) 
51) 61: Ne He ReAS XY LE bao meee 60) 
A constellation small in size but peculiarly 
rich in interest, lying between Cygnus, Draco, 
and Hercules. 

261.—Alpha (@) or Véga—sometimes written 
Wega—is one of the brightest of the first- 
magnitude stars, bluish-white in color, and— 
according to the chemistry of the suns—in the 
vigor of stellar youth. Vega is of special 
interest to us for at least three reasons. First, 
it is in the general direction of this star that our 
solar system seems to move in the depths of 
space, though the exact point lies within the 
bounds of Hercules; see the note on p. 66. 
Secondly, we may remember that while Alpha 
(a) in Ursa Minor is at present our Pole-star, 
being the nearest of the bright stars to the 
actual polar-point of the heavens, yet this 
polar-point is slowly shifting its position. We 
have already seen that 4000 years ago this 
point lay near Alpha (a) in Draco. See [161]. 
In the time of Hipparchus (c. 136 B. C.) it 
was about 12° from our present Pole-star; it is 


H Beginner's Star-Book 


now distant from it about 124°; it will gradually 
come nearer to it and in the next century will 
be only 1’ of arc distant. This distance will 
then increase; at length it will approach Deneb 
—-the brightest star in Cygnus—and then, 
about 12,000 years hence, it will be nearer to 
Vega than to Deneb, and Vega will be the 
Pole-star. Thirdly, it is of interest to know 
that Vega has a companion—rather difficult for 
a 3-inch, because of the extreme brilliancy of 
the primary, but available with a 33-inch or 
4-inch telescope. Mag. 0.1 and 10; A bluish 
white, B deep blue; distance=43”; p.=140°; 
R. A. XVIII h.°33.6 ms; Dieps8 2a 
distance of Vega from our system is 35 light- 
years; its proper motion, 0”.35. 
262.—Beta (f@) is a variable star; its period, 
I2 days, 21 hours, 47 minutes, and ranging 
from mag. 4.1 to 3.4. It is also a triple star in 
a 3-inch instrument and an easy double for a 
ene Mag. of two of components, 6.7 and 
; A-B, distance= 46", p =150 >-A=G die 
hie or" Oe). =BiSc aks a XVIII h. 46.4 m.; 
D.+33° 15’.. Arabic name, Sheliak. 
263 aeion (2) is ea famous double double. 
An opera-glass will show it double, a telescope 
of from 3 to 33 inches (depending somewhat 
on the eye of the observer and the quality of the 
object lens) will show each of these components 
to be itself a double. The beginner will need 
a high power, but the use of a power too high 
will make the field of view so small that both 
pairs cannot be kept in the field of the instru- 
ment. Each of these pairs is a binary, the two 
components revolving about a common centre 
of gravity; and the pairs in turn are probably 
also in slow revolution about a common centre 
of the whole system. We have perhaps a similar 
system in Castor (see [186]) though in that 
case the components of the two larger stars are 
too close together for separation in a telescope. 
In some atlases, Epsilon (€) in Lyra is classified 
as two stars, €' and &?, or @- and 5a Unemeue 
components are as follows: €’, mag. 5 and 6; 
é?, mag. 5 and 5; & yellow, €?, whitesee sae 
distance = 207" “Die 173 0) Ree XVIII h. 4I m. 
Dr30 7348 
264.—Eta (7) is a double star, though rather 
small for easy finding. Mag. 4.8 and 8; A 
blue, B violet; distance = 28"; p.=84°; Reed 
XIX h. 10.4 m.; D.+38° 58’. 
265.—Zeta (€), an easy and pretty double 
whether for a 2-inch or a 3-inch. Indeed a 
good field-glass, steadily held, will divide it. 
Mag. 4.3 and 5.9; A yellow, B greenish; dis- 
tance=44"; ; =149°; R. A. XVELieieee ies 
mer Do 3721308 
266. acta (6) j is also a wide double, an easy 
object for a field-glass or a very smali telescope. 
Mag. 4.5 and 5.5. A orange, B white; distance 
=750": R. A..XVIII h. 50.2 m:* Dieesoaraiae 
267.—Between Gamma (y) and Beta (f), and 


En Observer’s Catalogue 


somewhat nearer the latter star, 
the famous ‘Ring Nebula,” 


lies M 57, 
interesting but 


not impressive in a small telescope. Ie, aN 
Pov etd m.; 1D. 32° 53", 

Mi’-ra, see [1 a 

Mi’-zar, sce [401]. 

270.—M6n-6’-cér-6s, the Unicorn. (Maps pp. 


a5, 40. IN. H., Read VITh: 20 m.; D.—4°.) 
A large constellation of inconspicuous stars, 
lying between Orion and Hydra. 

271.—The star Beta ((/), sometimes marked 71, 
isa fine triple. Mag. 4.7, 5.2, and 5.6. White; 
A~ B, distance = sf 5, P-=133 ; A-C, distance = 
Boal ‘p.=108°; R eA V [eliened ems 16h tr 58’. 
272. —Epsilon (é) i is an easy double; the field of 
stars in which it lies is especially fine. Mag. 
4.5 and 6.5; A yellow, B blue; sees TAs 
Pea 200 kA. VI he 18:5 m.; Dees 

273. —Almost on a line between Deien (€) 
and Delta (6) will be found a star-cluster, 
marked in some atlases 2301, or 1465. It is in 
three branches. R.A. VI h. 47 m.; D.+0° 35’. 
274.—Not far from Epsilon (é) is a peculiarly 
beautiful cluster. It is marked in some atlases 
1424, or 2244. Its general direction from the 
star may be noted in the Night Charts of the 


constellation. It is a good object even for 
opera-glass or field- glass. Tree ORV bette 2 fain. 
D. +4° 56’. 


275.—otar-cluster 1637 or 2548, fairly large, 
and crowded with ninth- mage stars.) R.A: 
Niiiieneg sa. 1).—5 30’. 


285.—O-phi-i’-chus, the Serpent-Bearer. (Maps 
Pomoc eeN. EL.) Re As XVIT h. 20° m.: 
D.—5°.) <A large constellation, lying south- 
ward from Hercules and northward from Scor- 
pius. Its outline is peculiarly difficult to the 
beginner and its study may, therefore, well 
wait until other groups are learned. In study- 
ing it, remember that being able ‘“‘to see the 
man and the serpent”’ is of far less importance 
than the ability to recognize the constellation 
itself as a definite group of stars. First note 
that the Alpha (a) of this group is brighter than 
the Alpha (a) of Hercules, quite near it. 
Take then this brighter star as the apex of the 
triangle, Alpha (a), Beta (5), Kappa (2). See 
the map on p. 53. Then trace the right- 
angled triangle, Beta (f), Kappa (%), Epsilon 
(€). On a clear night this triangle is made 
more evident by noting that at each corner is a 
pair—Beta (f) and oman (v) at one corner; 
Kappa (x) and Iota (2) at the next, Epsilon 
(€) and Delta (0) at the third. Having learned 
this much of the group, the irregular line of 
stars from Epsilon (€) to Theta (9) is not diffi- 
cult. Serpens, the Serpent [365], divided by 
the above figure, lies in two parts—the head to 
the west or to the right, the tail to the east, 
or left; and the Serpent-Bearer, with head at 
9 


129 


Alpha (a), and shoulders at Beta (f) and Kappa 
(1), stands astride the serpent, with left hand 
grasping its coil at Epsilon (é¢), one knee at 
Zeta (¢) and one at Eta (7). The right hand of 
the figure also grasps the serpent at Nu (v7) 
in Serpens. See also [365]. Ophiuchus con- 
tains little of telescopic interest in a small 
instrument. The Arabic name of Alpha (a) 
is Ras Alhague. 
286.—The star marked 67 is an easy double 
even for a 2-inch. This and 7o are in an 
interesting field. Mag. 1 and 8; A yellowish, 
B purple; distance = 54" Si Da Ade eee 
XVIT h. 55.6 m.; D.+2° 56’ 
She tiie star marked 70 is also a double, 
though a little more difficult than the preceding. 
Rapidly changing binary: measures for IQII. 
Mag. 4.3 and 6; A yellow, B reddish; distance 
=o. 475 Dp: ss ReA wes VLU eis 0:4 9m 1D; 
+2° 31’. 
288.—In the region of Beta (/), slightly to the 
northeast, is a very pretty cluster of 8th mag- 
nitude stars, unmarked in many of the atlases. 
Itsepiace is indicated/in N..H:, R. Ay XVIEh. 
40 m.; D.+5° 40’. 
289.—A fine cluster marked in the Key-Maps 
as M12. It lies on a line between Epsilon (¢) 
and Beta (4); forming almost a right angle 
with Epsilon (€) and Lambda (A). R.A. XVI 
Deaoiie Di —1. 45% 


290.—O-ri’-on. (Maps pp. 41,45,49. N.H., 
R. A. V h. 26 m.; D. 0°.) On the whole the 
richest and most impressive of the constella- 
tions. The mythology of the constellation has 
taken so many forms that it is impossible to 
say which should have the precedence in age 
or interest. The group has always, however, 
represented a Giant Hunter. As sings Long- 


’ 


fellow in his ‘‘Occultation of Orion,’’— 


“ Begirt with many a blazing star 
Stood the great giant Algebar, 
Orion, hunter of the beast ! 

His sword hung gleaming by his side, 
And on his arm the lion’s hide 
Scattered across the midnight air 
The golden radiance of its hair.”’ 


According to one legend, the Giant Hunter 
was the companion of the Huntress Diana, 
who loved him and whom he desired to wed. 
Her brother, Apollo, was so opposed to their 
union that he caused the death of Orion by a 
scorpion’s sting. At Diana’s intercession, Orion 
was not only given a place among the stars, but 
was placed opposite to Scorpius (Scorpius 
always sets as Orion rises), that he might never 
again be troubled by the offensive reptile. 

The spectrum of most of the brighter Orion 
stars shows—despite the wide area covered— 
that they are much alike in physical constitu- 
tion and that they have, possibly, some physical 
connection—as if forming a loose but common 





130 


cluster. Betelgeuze [291] should probably be re- 
garded as an exception. Epsilon (€) and Gam- 
ma (vy), Alnilam and Bellatrix, are characteristic 
specimens. Stars which, under spectrum analy- 
sis, show that they are of the ‘“‘Orion type”’ 
are in the earlier stages of stellar development. 
They are extremely remote, most of them being 
at a light-distance of over 300 years, and—as 
is usual with the most distant stars—revealing 
a very small proper motion. 

291.—Alpha (q@), or Bét’-el-geuze, is the only 
marked ‘‘variable’’ among the first-magnitude 
stars, shining sometimes as a star of mag. 1.4 
and sometimes as mag. 0.9 (period about 200 
days), but never falling below the full first- 
magnitude standard. A singularly beautiful 
object, variously estimated as “red,’’-a ‘‘rich 
topaz,’ a, “reddish sorange.; etce) mucolorn 
In order to appreciate the real contrasts in 
star-color, the beginner should look alternately 
with his instrument at this star and at Rigel, or 
Beta (/), of the same group. Betelgeuze is a 
spectroscopic binary, see p. 143. In spite of 
its “brilhancy, 4tsis a distant Star eiteelioue 
taking more than a hundred years to reach us. 
It has a small proper motion, 0”’.03. It is 
not of the ‘‘Orion”’ type, but represents a later 
stage of development. R. A. V h. 49.8 m.; 
D7 a238e 

292.—Beta (4) or Rigel—pronounced Ree’-gel— 
is bluish-white in color, of intense brilliancy and 
beauty. It is one of the most remote of the 
brighter stars, being at a light-distance of at 
least 450 years. It is a double, separable, by a 
well-trained eye, under perfect conditions of 
light and air, with a 24-inch telescope. The 
companion is not especially close; but so great 
is the brilliancy of the larger component that, 
in order to see the smaller, the beginner will 
usually need a telescope of 3% or 34 inches 
in aperture. Mag.0.34 and 6.7; A pale yellow, 
By blues distance =9".5; p:=200 7 Re Away. oh. 
9.7 m.; D.—8° 19’. Rigel has no observable 
proper motion, nor motion toward or from us. 
In constitution it is conspicuously of the 
“Orion”’ type, tending toward the Sirian. 
293.—Delta (6), the “‘top star of the belt,’’ 
is an easy and beautiful object in a 2-inch 
instrument; indeed, after the eye has had a 
little experience, the star can be divided even by 
a good Iox field-glass. Mag. 2.5 and 6.9; 
A white, B violet; distance=53"; p.=360°; 
R. A. V h. 26.9 m.; D.—0° 22’.. Arabic name, 
Mintaka. 

2904.—The star Theta (0) is a quadruple, 
lying within the field of the great Orion-nebula. 
See illustration, p. 21. The nebula itself is 
one of the few that may be seen with satisfaction 
in small instruments. Naturally enough, the 
larger the telescope the better the'view, but 
even an opera-glass will indicate its existence. 
It shows to best advantage on a clear night when 





A Beginner’s StareBook 


there is little or no moonlight. The nebula is 
composed of luminous gases, and its distance 
from us, and the immensity of its proportions, 
are so great that we can form no conception of 
them except in vague and general terms. It is 


‘probably at a light distance of more than 250 


years, and its bounds probably exceed by many 
thousand times the area inclosed by the orbit 
of Neptune, our outermost planet. It seems 
to be receding from us in space at the rate of 
about 600 miles a minute. The star Theta (@) 
is itself of great charm and interest even in a 
2-inch telescope. The four components form 
what is called a “‘trapezium,’”’ an irregular 
quadrilateral. Mag. 6.8, 7.9, 5.4, and 6.9; 
A white, B lilac, C garnet, D reddish; A—B, 
distance =8”".7, p.=32 ; A-Cy)" dicstance=13 = 
p.=132°; A-D, distance=217) pp, —5ume ee 
V -h., 30.4 m.; D.—5° 27’. Large telescopes 
show the existence of several fainter stars in 
the trapezium group. 

295.—The star marked m is an easy double for 
small instruments. Mag 5 and 5.1; distance 
= 32" p.=28°; R.A. V h. 17,6 meee 
296.—Zeta (¢), the third star of the belt, is a 
triple, but it is not an easy object for an instru- 
ment smaller than a 34-inch. Mag. 2, 4.2, and 
10; A yellow, B purple, C gray; A-B, distance 
=2".8, p.=158°; A-C, distance = 57. amass 
9; R.A. V ho 35-7 me Dee 

297.—Iota (2) is the third-magnitude star just 
below Theta (@) in the Key-Maps. It bears 
no symbol, because the map here is crowded, 
but its identity—together with the smaller 
star to the right—will be evident. Iota (2) 
is a triple, but will appear only a double in a 
telescope of 3-inches or under. It is not easy 
with a 2-inch. The beginner will find the small 
stars in this immediate region somewhat con- 
fusing, at the first, but will soon learn to dis- 
tinguish them. Mag. 3, 7, and 11; A white, 
B pale blue, C red; A-B, distance=11”.5, 
p.=142°; A-C, distance = 40", p.=—103e;anumen 
V h. 30.5 m.; D.—5° 59’. Just to the west 
(or right, as observer faces south) of Iota (7) 
is a smaller star, a pretty double, also not 
marked in our charts because of the danger of 
overcrowding. It is listed here, however, 
because it is so easy and pretty as to be noted 
by almost any observer of the region round the 
great nebula. The technical name for the 
star is Struve 747. It is a good object for a 
2-inch telescope or even for a 10x field-glass. 
Mag. 4.7 and 5.6; distance=367-spu=ose 
RVAGV h3z0.dime Dlsbane 

299.—Sigma (0) is one of the most remarkable 
of the multiple stars, a quintuple, three of its 
components being visible in a 3-inch, or even 
in a 2-inch, telescope. Mag. 3.9, 5, 9.5, 6.8, 
6.3. A-B, distance=0”.3, p.=330; AB—C, 
distance=11".3, p.=237.; AB—D, distance= 
12”.8, p.=83°; AB-E, distance=41".4, p.=61 ; 


Zin Observer's Catalogue 


jah See AR PANS ey, 


E-D, ea. Ae 
ony Oca ee ae 

300. —Lambda ay the star that marks Orion’s 
head, is a triple; two of its components visible 
in a 3-inch. Mag. 3.7, 5.6, and 10; A yellow, 
DPerpucoisn: A-B, distance=4”".5, p.=—43°; 
Peemdistance—25".6, p.=183°; R. A. V h. 
29.6 m.; D.+9° 52’. 


301.—Pég’-a-sus, the Winged Horse. (Maps 


peemoemer te 55,43. - N. Hi R. Av XXII h. 
50 m.; D.+20°.) A large constellation, of 
marked general interest because of the “‘great 
square’’ for which it is conspicuous. This is 


formed by its stars Alpha (a) or Markab, 
Beta (/) or Scheat, Gamma (y) or Algenib, and 
the Alpha (a) of Andromeda. But it has few 
objects for telescopic study. 

When the head of Medusa was struck off by 
Perseus, Pegasus—the Winged Horse—sprang 
from the blood of the Gorgon. Pegasus was 
afterward caught by Bellerophon with the 
golden bridle, gift of Athena. The hero then, 
after his triumph over the Chimera, attempted 
to ascend to the heavens on his winged horse. 
He fell to the earth; but Pegasus, ascending, 
was given a place in the stars. For the con- 
nection (?) of Pegasus with Perseus and An- 
dromeda, see [1]. But this connection belongs 
to a much later legend. 
302.—Epsilon (€) is a wide double star. Mag. 
2.5 and 8. 5;A yellow, B violet; distance = 138"; 

pe=e2e RAL XX] h. 30.3.mn.; D.+9° 25’. 
Kae name, Enif. 
303.—The cluster marked M 15 is globular in 
form, looking somewhat like a nebulous oval 
in a small telescope; but revealing its star- 
structure in larger instruments. R.A. XXIh. 
25.1 m.; D.+11° 44’. 
304.—The little star Pi (7) has near it another 
marked in some atlases as 7”. The pair make 
a pretty object for a 2-inch, or for a field-glass. 
The stars are of mags. 4.4 and Se7 kee XXII 
Pas See)? 32° 41’, 


305.—Per’-se-us. (Maps pp. 59, 55, 43, 47. 
Peete oe Lil h.20:m.: D.-+-45°.) A rich 
and brilliant constellation of the northern sky, 
somewhat irregular in form, lying between 
Auriga and Cassiopeia. The breast of the 
hero is supposed to be at Alpha (a), the head 
at Gamma (/), one hand grasping his sword at 
the cluster h-y, and the other holding the 
head of Medusa at Beta (f). One knee is at 
Mu (#), the other at Xi (&). For the story of 
Perseus, see [1], in connection with Andromeda. 
306.—The star Alpha (a) lies directly within 
the Milky Way and is the centre of a brilliant 
field of stars. There are few finer spectacles, 
whether for the opera-glass, the field-glass, or 
the small telescope. R. A. III h. 17.2 m.; 
D.+49° 30’.. Arabic name, Algenib or Marfak. 


131 


307.—Beta (f) is the famous variable, Algol, 
aiscucsedmonm pm iq. elk- vA. Lie hy 3-7 im.: 
D.+40° 34’. 

308.—The star Eta (77) is a double for a 3-inch. 
Mag. 3.9 and 8.5; A orange, B blue; distance = 
Ba = 2007 Ae hee i 520%, 
309.—The double star-cluster h—-y is one of 
the very finest in the sky, and is peculiarly 
beautiful in small instruments. The use of 
high magnifying powers will necessarily reduce 
the size of the field and the impressiveness of 
the spectacle. On a 3-inch the best eyepiece 
to use is one from 25x to 40x; on a 2-inch 
telescope, use I5x to 25x. On telescopes of 
other apertures use powers proportionately 
low. See the illustration, Os ee Le h. 
14 m.; D.+56° 40’. 

S10: —Zeta (£) is a quadruple star; though a 
small instrument will show only two of the 
components. It is not easy for any telescope 
smianlersthan a 35. Mac. 3, -9.3,.10, and 11; 
A white, Band C blue. A-—B, distance =12”.8; 
D207 BRA wl lehe 47m: ete sr. 
311.—A fine star-cluster marked M 34, a good 
object for a 2-inch or 3-inch telescope, lies on a 
line from Gamma (vy) in Andromeda to Beta 
(#) in Perseus. R.A. IL h. 36 m.; D.+42° 21.’ 


320.—Pis’-cés, the Fishes. (Maps pp. 61, 41. 
NE ReeA Och: 30m. 2Di-E15-.)) F Avlarce 
constellation, lying in the track of the planets, 
between Aquarius and Aries. It is import- 
ant because of its position, but it has few 
brilliant objects of telescopic interest. 
321.—Alpha (a) is a fine double, but the com- 
ponents are so near each other as to be a little 
difficult with a 3-inch, and the distance seems 
to be decreasing. It is worth trying with a 
3-inch, however; and a little experience, with 
good atmospheric conditions, will bring success. 
Mag. 4.3 and 5.2 ; A pale green, B blue; distance 
Pe 9320. : REASLA 56.9 m.; D.+ 2°17’. 
Arabic name, El Rischa. 

322.—Zeta (6) is an easy and pretty double 
star lving between Mu (/) and Epsilon (¢). 
Mag. 5: 6 ‘and 6.5; A white, B grayish; ee 
Sh ee Ole ee Ae ges s eng Ds-7 
323.—Psi (aby marked yt in some atlases; th 
easy double. Mag. 5.6 and 5.8; both white; 
distance—400 pe=160-> Ree A. Loh. 0:4: 
D.+20° 56’. 


330.—Pis’-cis Aus-tri’-nus, the Southern Fish. 
(Map p. CUMIN gr toe oO het 541d. se): 
—30°.) Not to be confused with Pisces, the 
Fishes; see above. A southern constellation 
chiefly characterized by the fine first-magni- 
tude star Fo’-mal-haut (Fo’-mal-6), which is 
supposed to mark the Fish’s mouth. It lies 
south of Aquarius, and is a conspicuous object 
in the southern sky during the early evenings 
of autumn. 


132 


331.—F0’-mal-haut (pronounced F6’-mal-s), to 
which reference has just been made, has a 
distant companion; dif. in R. A. 4.8 sec.; p.= 
195.; mag. of the two components 1.3 and 9.5. 
Many astronomers would rightly contend that 
stars so far apart should not be classified as a 
true double. But Smyth does well to list it 
because of the general interest in all first- 
magnitude stars. The dull blue companion is 
by no means easy. R. A. XXII h. 52.1 m.; 
D.—30° 9’. Distance of Fomalhaut is 24 light- 
years; proper motion, 0”.37. In general type, it 
resembles Sirius [66]. 

332.—-Beta (/) is an interesting double star, 
even in a 2-inch instrument. Mag. 4.4 and 
Vey distance = 30"; 32 SY Pe ese OBE My 
oe 9 m.7 325 

Boas Gamma (vy) ie a double also but not so 
easy as the preceding. Mag. 4.5 and Bes 
distance = 4"; 2 70 en eas “XXIT h. Af ane 

Diz-33.024 


Plei’-a-des, see [382]. 





P6-lar’-is, see [406]. 

Pé6l’-lux, see [187]. 

Pre’-se-pe, see [52]. 

Pr6o’-cy-on, see [71]. 

Pup’-pis; Pyx’-is, see [25]. 

Rég’-i-lus, see [226]. 

Ri’-gel, see [292]. 

335.—Sa-git’-ta; the Arrow. (Maps pp. 57, 
GIe5I NOH. Ro AW LS hao ms Dies) 
A small constellation lying in the Milky Way 
slightly to the north of Altair. It is of interest 
to the eye because it really looks like an arrow. 
Between Delta (6) andGamma (vy), and slightly 
below a line connecting them, there lies a small 
cluster marked in some atlases M 71 and in 


others 4520, or 6838. It is not impressive in 
a small instrument.) .RieA. X1X “Geedo eam: 


DAIS. 41% 
340.—Sa-git-ta’-rius, the Archer. (Maps pp. 
573, SOpeO Lie No Lider comes (OX Oe nT mere 


—25°.) A large constellation, in the track of 
the planets, between Capricornus and Scorpius. 
The constellation is not rich in double stars, 
but it presents a fine spectacle to the unaided 
eye and it lies in a region crowded with nebule 
and star-clusters of great beauty. 

341.—The object marked M 8 is, under good 
atmospheric conditions, visible to the naked 
eye. It can be found by projecting a line 
from the star Phi (~) to Lambda (A) and con- 
tinuing it an equal distance. The cluster is 


just below the termination of the line. It is 
a cluster superposed upon a fine nebula. See, 
however, the illustration. on p. 115. R. A. 


XV ish 57: gems 4 oo 


AH Beginner’s Star-Book 


342.—Just north of the preceding object and 
more nearly at the termination of the line just 
suggested is the rich nebula marked M 20. 
It is sometimes called the “Trifid’’ nebula, 
because of its triple form. R.A Xx Vii 


56.3. ine a= 23m oe 


343: —The cluster M 22 lies on a line drawn 
from Tau (T) to Sigma (o), continued about 
half as far again. It is a beautiful and impres- 
sive object. R. A. XVIII hizo eeineae 
—23 58’. 

344.—This, marked M 17, is the famous Omega 
nebula, thus called by reason of its supposed 
resemblance to that Greek letter. It is ir- 
regular in form; a fine object. R.A. XVIII h. 
14.9 m.; D.—16° 13’. 

345.—This cluster, M 24, is not far from the 
above, a little to the north or just over it and 
tothe left—as we face southward. R. A. 
XVI bi 13 sD ome oe 

346.—The multiple star Mu (/), omitted from 
the Night Chart in order to avoid over-crowd- 
ing, is indicated in N. H. It is a fourth- 
magnitude star lying almost midway between 
M 8 and M 24, alittle nearer the latter. While 
the star is a quintuple, a 3-inch instrument 
will probably show but two of the components 
to the average eye. Mag. 3.5 and 9.5; distance 
= 48". 33 P. Se wien 48S: A. XVII yee 
Di 3b ase 





350.—Scorp’-i-us, the Scorpion. (Maps pp. 
53, 57; N. H., Ri A. XVI Wt es an ere 
The name of the group is sometimes written 
Scorpio. It is a large and important constel- 
lation lying in the track of the planets, between 
Libra and Sagittarius. It presents an impres- 
sive field of stars, beautifully grouped and 
bearing much likeness to the object for which 
it has been named. Indeed it looks more like 
the real scorpion of the tropics than do some of 
the weird illustrations of it presented in our 
mythological star-maps. 

351.—Alpha (qa), or Ant-a’-rés, is one of the 
finest of the first-magnitude stars, somewhat 
varying in hue, but predominantly red. Hence 
its name Antares, opposed to, or rivalling, Mars, 
—Mars being of course the red planet. It was 
also called Kapsila xopntov by the Greeks, 
Cor Scorpionis by the Latins, and Kalb-al- 
’akrab, by the Arabs,—all meaning the Scor- 
pion’s Heart. It possesses a small companion 
star, but the components are not easily sepa- 
rable except in a telescope of 33-inches or 
over. Some observers claim to have seen the 
small star with a 3-inch, under fine atmospheric 
conditions, but the average eye will require a 
larger instrument. Mag. I. 2 and 7; A red, B 
blue: distance = 3"; | D- = 275°; » Rin Are Nev eanes 
23.3m.; D.—26° 13’. It is also a spectroscopic 
binary; p. 117, col. 2. Its distancemissover 
a hundred light-years, but it is drawing nearer 


Zin Observer's Catalogue 


to us at the rate of about 100 miles a minute. 
In constitution it represents a type far advanced 
in development. 
352.—The star Beta (4) is a fine double even 
in a 2-inch telescope. Mag. 2.9 and, 5A 
white, B lilac; distance = 13.” 53 P. =24 .A sR: 
A. XV h. 59.6 m.; D.—19° 32’. 
353-—Nu (v) is a fine quadruple in a large 
instrument and a very satisfactory double 
even in a 2-inch telescope. Mag. 4 CAS ae7. 
and 8; A-B, distance = 1"; s==300-- C1), 
distance = 2"; 44°; AB- ie: distance = 41"; 
320 oR, A. XVI hb. 6.2 m.: -D. Sais ape 
ahi ~The little star Xi (S) ‘is a good object 
for a 3-inch or 2-inch, lying in a fine field 
directly north of Beta (/); the star below 
Scorpius bearing the same symbol is in Lupus. 
Mag. 4.6, 5.5, and 7.1; A white, B yellowish; 
PeUerdiccance=0".7: p.=2290 .6; A-C, dis- 
tance —ganp.—65 ; R.A. XV h. 58.9 m.; D. 
—11° 6’. Bis not visible in small instruments. 
355.-—The fine star-cluster marked M 8o lies 
just half-way between Alpha (a) and Beta (f). 
In a small instrument it has the appearance of 
aenepula Rk. A: XVI h. 11 m.; D.—22° 44’. 
356.—The star-cluster M 6, when sufficiently 
high above the horizon, may be discerned even 
with the naked eye. It is composed of stars 
from mag. 6.5 to 9, and is a fine spectacle in 
the telescope. R. A. XVII h. 33 m.; D.— 
32° Q’. 
357.—Another star-cluster, marked M 7, is not 
far from the preceding object—both lying very 
near the border of Sagittarius—and is also a 
fine object for those who are observing far 
enough to the south to get a good view of it. 
Re A. DOV haa7 m.; D.—34° Apes 
358.—The star Sigma (0) is a double, but it is 
not an easy object for a telescope smaller 
than a 34-inch. Mag. 3 and 9g; distance= 
20” ‘53 P- ,= 272°; eee AC CV le Gel Seka tlk). 
—25° 21’ 
359.—Mu (4), a wide double star, sometimes 
marked #* and “?; mag. 3.1 and 3.6; difference 
of R. A.=28 see: ee Oe V lela 4S tern: 


ey 634 - 


360.—Sculp’-tor. (Maps pp. 61, 41. S. H., 
R. A. 0 h. 30 m.; D.—33°.) A small southern 
constellation, south of Cetus and Aquarius, 
and just to the east of Piscis Austrinus. It 
possesses few objects of telescopic interest. 


365.—Ser’-pens, the Serpent. (Maps pp. 53, 
57a... RR. A. XVI h. 45 m.; D.+5°.) 
An irregular and not very important eee! 
tion lying on both sides of Ophiuchus, the Ser- 
pent-Bearer [285]. The part toward the west 
is often called Serpentis Caput, or the Serpent’s 
Head; that to the east, Serpentis Cauda or the 
serpent’s Tail. 

366.—Beta (f) should first be examined with 


133 


lowest power. The field near it, especially a 
little way to the northeast, is a fine spectacle 
even for the opera-glass or field-glass. The 
star itself is a double for a 3-inch, but not easy. 
Mag. 3.8 and 9.2; both blue; distance = 30" 6; 
p.=265°; R. A. XV h. 41.6 m.; D.+15° 44’. 
an —Delta (6) is also a double, not quite so 
difficult as the preceding. Mag. 4.2 and 5.2; 
both white or bluish; distance = 3" Geeer oe 
Reta, DON Ge ee saree JD Re Sako 
368.—Theta (6), on the other side of Ophiu- 
chus from the above, is easier than the stars 
just named; one of the finest objects in the sky 
for a small instrument. The components are 
mag. 4.5 and 5.4; both yellow; Gee 
Des 104 eRe A eV Tihs S12 ms D.-4" 
This star terminates a slightly arched tie “ot 
four stars, the other three being the Theta 
(9), Eta (7), and Delta (6) of Aquila. Con- 
tinuing this line about as far to the west (right) 
as Delta of Aquila is to the east (left), the 
observer will find a singularly beautiful cluster, 
marked in some atlases 4410, and in some 6633, 
but not charted in the Key-Maps. 
369.—Nu (¥) is also a double for a 3-inch, but 
not so easy as the preceding; mag. 4.3 and 8; 
A silvery, B dull lilac; distance =48"; p.=32°; 
1 AN, PANES Bllnes 7 ger>rurone 3 JOR oag eo or 
371.—M 5, a small circular cluster sometimes 
listed as 5904—many of the stars of w pe it 
is composed are variable. R.A. XV.h. 13.5 
Tie) e527, 


375.—sex’-tans, the Sextant. (Maps Pp. 49, 
(ices ONG reese ele 1 Ontnig b)s— 2 3) 
A small and unimportant constellation, lying 
between Hydra and Leo. 


Si’-ri-us, see [66]. 
Spi’-ca, see [416]. 


380.—Tau’-rus, the Bull. (Maps pp. 41, 45, 59, 
A7eEN Re Ae Ven 20 cir, el, pA 
large and important constellation, lying in the 
track of the planets, between Aries and Gemini. 
In the lore of the Egyptians, who identified it 
with Osiris, as well as in that of the Greeks, 
this group has been called “the Bull,’’ and has 
always assumed peculiar importance. In the 
Greek legend the bull is the form taken by 
Zeus in his capture of the fair Europa. She, 
the daughter of Agenor, was sporting with 
her maidens upon the meadows when she 
essayed to mount a beautiful white bull which 
was feeding near. This was Zeus in disguise; 
he dashed into the sea and bore her away to 
Crete. Only the forequarters of the bull are 
outlined in the stars,—the explanation being 
that as he swims the rest of the body is covered 
by the waters. For another legend see p. 44. 
381.—Alpha (a), or Al-déb’-a-ran, is often 
regarded as a standard first-magnitude star, 
Sirius and several others being much brighter 


134 


than the standard, and Regulus, Deneb, etc., 
being below it; p. 140. Aldebaran is a double, 
but difficult for an instrument smaller than a 
33-inch. Mag. 1 and to. A reddish, B blue; 
distance =118".9; p.=35°.2. The distance of 
Aldebaran from us is 45 light-years, about that 
of Capella [36] or Arcturus [41], and is growing 
34 miles greater every second. Its annual 
proper motion is 0”.2. In physical develop- 
ment, it is rather far advanced, but less so than 
Antares [351]. RwA SL Ve 30.250 Oye 168 


age .—The Plei’-a-dés compose not only the 
finest star-cluster in Taurus but the richest and 
most interesting in the sky. The Biblical 
references to the group (Job ix. 9; xxxvill. 31; 
Amos v. 8) and the references of Hesiod 
(nearly 800 B.c.) show it to have been one of 
the earliest objects of astronomic interest. The 
illustration on p. 18, from a photograph (en- 
larged) taken at the Yerkes Observatory, shows 
the group about as it appears in the northeast. 
The largest and brightest of the stars, at centre, 
with image blurred, is Al-cy’-on-e. The two 
larger stars below are Atlas (to the reader’s 
right) and Plei’-on-e, to the left. A line run 
upward between these stars, through Alcyone 
and onward, will pass through Elec’-tra. To 
the right of this line is Mer’-o-pe; to the left is 
Ce-le’-no, then two stars brighter than Celzno, 
called Mai’-a and Ta-y’-geta, Maia being the 
lower. ‘Then, still farther to the reader’s left, 
come two smaller stars, quite near together, 
the upper called As-té’-ro-pe I and the lower 
Asterope II. They appear as one to the 
average unaided eye, and are thus called 
simply Asterope. The star farther to the left 
has no name, merely the symbol m. The 
beginner may not care to memorize these 
names; they are given, however, for purposes 
of reference. As the group swings southward 
in its course and culminates, it slowly turns till 
Merope becomes the lowest star, with Atlas 
and Electra to the left and right; Electra 
gradually leading the way and becoming the 
lowest of the group as the Pleiades sink to- 
ward the west. The image of Alcyone, the 
central star, seems blurred in our illustration 
because there are three small companions 
quite near it. Bee below (284 aee ewer lets 
41.5 m.; D.+23° 

383. —The Hy ave This cluster of stars 
is only less beautiful and impressive than the 
preceding. It is even more widely scattered; 
and it presents so much of variety and contrast 
that it affords a field of peculiar splendor and 
charm for the low powers of the small instru- 
ment. R.A. (about) IV h. 23 m.;D.+15° 44’. 
384.—Eta (7) or Alcyone, the brightest star 
of the Pleiades, may be observed as a triple 
even in a 2-inch telescope: there is another 
component not so easily detected, but a 3- 


making a charming spectacle. 


HH Beginner’s StarzBook 


inch will usually show in addition to the pri- 


mary, the whole triangle of little stars. Mag. 
3.1, 7, and 7; A-B, distance = 120"; p.=2007; 
A- CG distance, ue F p.=344.. Riga ee 


AT.5n.; 1.23) 


-386. —Theta (6), sine marked 0" and @0?, isa 


wide double star, on a line connecting Alpha 
(a) andGamma (vy). <A good object for opera- 
glass, field-glass, or small telescope. Mag. 
2.0 and 4; A white, B yellowish; distance = 
cere ; P-= 346°. R. A. IV hve23 eee 
15) 44’. 

387.—Tau (7), an easy double, a little way off 
a line connecting Epsilon (€) and Beta (f). 
Mag. 4.3 and 7; A bluish-white, B lilac; dis- 
tance=63"; p.=213°; R. Ay [Ve neecoeene 
D.+22° 46’. 

388.—The star marked Jo is at extreme south- 
western limit of the constellation,—it is some- 
times included in Eridanus. It is not itself a 
double—though wrongly so classified in some 
atlases—but quite near it is an easy and pretty 
double known technically as “Struve 422.” 
Mag. 6.3 and 8.5; A golden yellow, B blue; 
distance =6".5; p.=250 ; Ry Am iiispeiegnan 
D.+0° 16’. 

389.—Sigma (0) is a wide double for the opera- 
glass or for other low powers. In a glass 
having good illumination and wide field this 
pair may be seen with Theta (@), (see above), 
the two couples with the surrounding stars 
Mag. 4.8 and 
5.2; both white; distance = 429"; p.= 102". 4; 
R. A. IV h. 33.4 m.; D.+15° 43’. 

391.—Phi (9), a double star; mag. 5.1 and 8; 


A reddish, B blue; distance = 50": p.= 250°; 
R. A. IV h. 14.2 m.:; Del27ae 
395.—Tri-an’-gi-lum, the Triangle. (Maps 


pp. 41, 61,55, 59: N. H., ReeAn Ieee 
+32°.) A northern constellation lying be- 
tween Andromeda and Aries. 

396.—This is the beautiful nebula marked 
M 33. It lies just off a line from the Alpha 
(a) of Triangulum to the star Beta (f) in 
Andromeda, and while not a brilliant object 
in a small instrument is of much intrinsic 
interest. See the illustration, p. 36. R. A. 
Ths 26,7) ms De 30, 108 


400.—Ur’-sa Ma’-jor, the Great Bear, or, liter- 
ally, the Greater Bear. (Maps, all northern. 
N.H.,R. A. Xh. 40 m.; D.+56°.) A large and 
important constellation, well-known by reason 
of the seven bright stars which form the Great 
Dipper,—called in England ‘‘The Plough”’ or 
“‘Charles’s Wain”’ (wagon). The stars forming 
the handle of the Dipper are regarded, in the 
English usage, as forming the tongue or shaft 
of the plough or cart (see also p. 23). The 
manner in which the stars are supposed to 
suggest the figure of a bear is indicated on 


Ein Observer's Catalogue 


pp. 38, 54. The Arabic names of the chief 
stars are as follows: a, Dubhe; £, Merak; 
7, Phecda; 6, Megrez; ¢,. Alioth; €, Mizar; 
7, Benetnasch. 

According to the Greek legend, the nymph 
Callisto, beautiful daughter of Lycaon, King 
of Arcadia, excited the jealousy of Hera. 
Zeus, in order to save her from the wrath of 
his spouse, changed Callisto into a bear and she, 
wandering in the forests, met her son Arcas, 
who raised his spear to strike her. Zeus 
prevented the tragedy by placing both among 
the stars, where they became the Great and 
Little Bears. Hera was still unappeased, and 
at her instigation, Oceanus and Tethys ordered 
that they should forever pursue their course 
about the Pole, never passing with the other 
stars to their rest beneath the waves. 
401.—The star Zeta (€) or Mi’-zar, located at 
the bend of the Dipper’s handle, is one of the 
most interesting objects in the heavens. It 
is, first, a “‘double’’ even to the unaided eye, 
for the little star marked g (named Alcor) 
belongs to the same system. An opera-glass 
will show this little star, but a good eye should 
be able to detect it without optical assistance. 
Secondly, Mizar proper—the larger of the two 
stars—is a charming telescopic double, even ina 
2-inch telescope. An eyepiece with a power 
of from 25 to 50 on a 2-inch or 3-inch will 
clearly divide the components. Thirdly, it is 
most interesting to know that there is a still 
further division; that each of these objects 
is in fact a binary pair—the members of each 
pair too near together to be separated by any 
possible telescope. Mizar was the first spectro- 
scopic binary to be discovered. W.W. Bryant, 
in his History of Astronomy, p. 300 (London, 
1907), makes this interesting note: ‘‘ Curiously 
enough, Mizar was also the first recognized 
visual double star, having been noted at 
Bologna by Riccioli in 1650, and also the first 
photographed as such, by G. P. Bond in 1857; 
moreover there is every probability that Mizar, 
with Alcor, was the first, as it is certainly the 
best known, ‘naked eye’ double star, the names 
having been given by the Arabs.’ The 
brighter component of Mizar is revealed by 
the spectroscope as two suns revolving once in 
every 20.5 days about their common centre 
of gravity. They are really about 36,000,000 
miles from each other, their combined mass 
being about 20 times that of our sun. A 
fourth fact about Mizar is that this quadruple 
system is not at rest in space, nor receding 
from us, but is approaching us at about 8 
miles a second, or 28,800 miles an hour; p. 138. 
So vast, however, are the depths of space, 
that such motions are not likely to bring the 
star visibly nearer to us even in many millions 
of years. Mizar is so remote that its very 
light takes about 99 years in which to reach our 


135 


earth. The mags. of the telescopic double are 
2.4 and 4; A white, B pale emerald; distance = 
(Ae Orme eS LLM eho .Oe ins: mL). 
K5e20', 

402.—The little star marked g, Alcor by name, 
is an easy object for the opera-glass, or even 
for the unaided eye, if the air be clear. See 
above [401]. It has recently been ascertained 
that Alcor itself is a spectroscopic binary. The 
position angle of this star in relation to Mizar 
is given by Smyth in 1839 as 71°.7; the distance 
Sat NetOp 1) he 20.27 We -+-55, 30°: 
403.—Sigma! (@') makes with 0? a good opera- 
glass object, for Rho (p) is in the same field. 
Sigma’? (7) is a double star, though a little 
difficult even for a 3-inch instrument. Mag. 
4.9 and 8; A white, B blue; distance=2”; p.= 
ose Ale SUB Slay Vide arene DLS 6p) eae 


405.—Ur’-sa Mi’-nor, the Little Bear, literally, 
the Lesser Bear. (Maps, allnorthern. N. H., 
R. A. XV h. 9 m.; D.+79°.) The nearest of 
all constellations to our present celestial Pole, 
including the polar-point within its bounds. 
The group of stars is recognized by the figure 
of the “‘Little Dipper.”’ The two stars which 
mark the front edge of the Dipper, Beta 
(8) or Kochab, and Gamma (y), are called 
the Guardians of the Pole. 

406.—Alpha (qa), or Po-la’-ris, is the most 
important star in the sky—because of its 
position near the Pole of the heavens, see 
p. 23, and its relation to navigation and com- 
merce. It is also of deep interest on its own 
account. We shall see that Polaris is a tele- 
scopic double. But in addition to the gth- 
magnitude companion revealed in the telescope, 
the spectroscope shows that the primary star 
is a triple; the two elementary components 
revolving about a common centre of gravity in 
about 4 days (3.97), and the pair revolving 
about a third member of the system in approx- 
imately I2 years. In preparing to view the 
telescopic companion, the beginner is likely to 
assume that because Polaris is at the Pole, the 
companion will always be in the same apparent 
position in reference to the larger star. Even, 
however, if Polaris were at the exact Pole, the 
companion star would have to make its revo- 
lution about the polar-point. But Polaris is 
not precisely at the Pole. In fact it is (1912) 
1z° distant; two moons might be ‘driven 
abreast’’ between the Pole-star and the actual 
Pole. Polaris, therefore, revolves about the 
Pole as does every other star; and while the 
position angle of the two components remains 
the same, the apparent direction of the smaller 
star, in relation to the larger, varies necessarily 
from hour to hour. Viewed in an astronomical 
telescope on Nov. 1 at 8 p.M., for example, 
the smaller star will be directly below the 
larger; at the same hour on Jan. 1, it will be 


136 


below and toward the right; Feb. 1, directly 
to the right; April 1, to the right and upward; 
May 1, almost directly above; June 1, above 
and to the left; Aug. 1, almost directly to the 


left; Oct. 1, downward and to the left; Nov. 1, _ 


directly downward or below, as already stated. 
The positions for the intervening hours can 
easily be estimated; or it can be remembered, 
in general, that during the early evenings of 
October, November, and December the smaller 
star is below the larger; during the early even- 
ings of April, May,and June it is above the 
larger; is to the left of the larger during: the 
early evenings of July, August, and September; 
and to the right of the larger during the early 
evenings of January, February, and March. 
Space has been given to this statement be- 
cause Polaris is one of the most fascinating of 
objects to the average observer with a small 
instrument, and yet the beginner does not 
always know in which direction to look for 
the small companion. It is often said to be an 
easy object for a 2-inch telescope. But astron- 
omers who make such statements usually do 
so on theoretic grounds and because they have 
little practical familiarity with the limitations 
of the average eye and the small telescope. 
False expectations are thus created which lead 
to disappointment and discouragement. It is 
seldom indeed that any average eye, without 
training in observation, can divide the star 
with a 2-inch. Few beginners can do it with 
a 24-inch. Success will not often come, at 
first, even with a 3-inch. But with any tele- 
scope of 24-inches and upward the novice 
should make repeated trials, using powers 
from 75 to 100. Under the right atmospheric 
conditions a much lower power willavail. Suc- 
cess will come with a little experience. Mag. 
2.1 and 8.8; A’ yellow, B bluish; distance= 
105 p.= 215 ee lel OliD ae ee 
46’. 

Vé’-ga, see [261]. 


415.—Vir’-go, the Virgin. (Maps Pp. 49, 53. 
IN THe, Ree eT heer 6c 0 eee 
large constellation, lying in ‘the track of the 
planets, between Leo and Libra. The triangu- 
lar space bounded by lines from the star Beta 
(f) to Gamma (yv), and from Gamma (vy) to 
Epsilon (€) is a region of many nebulae. They 
are not individually remarkable in small 
instruments but the field should be studied, 
using a low-power eyepiece,—about 30 to 40 x 
on a 3-inch telescope. Besides the stars of 
telescopic interest, Virgo has a third-magnitude 
star, Epsilon (€) or Vindemiatrix. See p. 48. 

416.—Alpha (@), or Spi’-ca, is one of the finest 
“Jandmarks” of the southern sky; see p. 26. 
It is a star of the first magnitude, so far dis- 
tant that, in order to account at all for the 
intensity Of its light, it has ‘been estimated to 


HH Beginner’s 


StareBook 


be at least 1000 times more luminous than our 
sun. The spectroscope shows it to be a binary, 
the two components revolving about their 
common centre of gravity in a little over 4 


days. Spica has, for the telescope, a small 
neighbor star. Mag. of Spica, 1.21; of the 
companion, 10; colors, A white, B bluish; 


distance =359".8; p.=61 .0; Ihumiummala anne 
19.0-10.7 D.—10° 38’. Its proper motion is 
annually only 0”.05; its constitution is of the 
“‘Orion”’ type, see [290]. 

417.—The star Gamma (y) is one of the most 
interesting and satisfactory objects within the 
range of small telescopes. It is a binary, the 
two components completing their revolution 
about their common centre of gravity in about 
194 years. In 1834 they were so close together, 
as viewed from the earth, that no telescope 
then in existence could separate them. They 
have now swung farther away from each other 
in their course and the pair can be easily 
divided by a good 2-inch instrument. A power 
of 50 on a 2-inch or 3-inch telescope is adequate. 
Mag. 3.7 and 3.7; A white, B yellow; distance 
(1911) = 6"; p.= 326°; RAS oroner. 
D.—0° 

418. Theta (9) is a triple, but not an easy 
object even in a 3-inch instrument. oe 
4.4, 9, 10; A white, B violet, C dusky; A-B 
distance =7".1 13 pi==344 oe et distance = 71" 
Di=207.> Raion 4.8 m.: D.—5° 0’. 
419.—Tau (7) is a double, for a 2-inch or 3- 
inch telescope. The beginner will usually 
require a 3- -inch, Mag. 4 and 8.5; distance = 
70! 1, = 200 ea eG XIII h. 56.6 m.; D.+2° 2’. 


425.—Vul-péc’-i-la, the Fox. The group is 
sometimes known as Vulpecula et Anser, or 
the Fox and the Goose. (Maps pp. 61, 51, 
57. N. H., R. A. XIX” he To eae 
A small and unimportant constellation lying 
between Sagitta and Cygnus,—easily found 
near the foot of the Northern Cross. © 
426.—The star marked 6 forms a pretty pair 
with a neighbor star,—marked § in some 
atlases;—a good object for opera-glass or field- 
glass. Mag. 4.6 and 6; distance=403 suk. 
A. XIX h. 24.5 m.; D.+24° 28’. 

427.—The nebula marked M 27 forms an 
acute triangle with the stars marked Eta (7) 
and Gamma (y) in the neighboring constella- 
tion, Sagitta. This has long been known as the 
‘‘Dumbbell Nebula,’’ because as viewed in 
the telescope it was thought by some observers ° 
to resemble a dumbbell. It has little resem- 
blance to such an object, except that there is a 
narrowing and thinning of its faint effulgence 
across its central zone. As with most of the 
nebula, a glimpse of it may well be interest- 
ing to us, but it is not an impressive object in 
small instruments. R. A. XDXO@hees sea, 
D.+22° 2 


HALLEY’S COMET, MAY 26, 1910 


From a photograph taken at the Lick Observatory 





UTI. Star Distances, Star Motions, Magnitudes, ete. 


WE have seen, p. 9, that the stars are at such vast distances from us that the unit of 
measurement is the “‘light-year,’’—the distance traversed by light, at a velocity of over 
186,320 miles a second, in a year of time. To find the distance of a star, the astronomer 
must determine its parallax—the angle subtended at the star by the radius of the earth’s 
orbit. Although this base line represents the distance between Earth and Sun, or approxi- 
mately 93,000,000 miles, there are multitudes of stars which show no parallax. Indeed 
they are so remote that a line representing the whole diameter of the orbit, or over 185,000,- 
000 miles, assumes but the aspect of a vanishing point in the perspective of the star’s dis- 
tance. Bessel, a great German astronomer, obtained (1838) the first satisfactory measure 
of a parallax,—that of the small star known as 67, in Cygnus. It was long thought to be 
the nearest visible to the unaided eye from our latitudes, but this position now belongs to 
Sirius. A telescopic star, ‘Lalande 21,185,’’ is the nearest known in the northern skies. 

In the following table the parallax of the stars is indicated in the column marked P. 
These parallaxes have been obtained by different astronomers, but they are here presented 
from the list of Kapteyn and Weersma, Groningen, 1910; Kapteyn being the most generally 
accepted living authority on the general problem of stellar distances. They are not all 
entitled to equal weight. I have, therefore, ranked them in the col. marked F according 
to the degree of finality which should probably be accorded them. For these estimates of 
finality K. and W. are not responsible. A parallax classed as A is probably accurate 
within 0”.02; a parallax classed as B is probably accurate within 0”.03 or 0”.04; and C, 
within 0”.05 or 0.”06. In the column marked D is noted the distance of the star in light- 
years, based on the parallax given. The greater the distance, the more uncertain become 
all the conditions involved, so that the figures for stars at a light-distance exceeding 100 
years become necessarily more like approximations than like rigid calculations. In many 
cases, however, these approximations are as likely to be underestimates as overestimates. 
Where a negative parallax is indicated (by the minus sign preceding) the star is too far 
distant to be measured at all, and the light-distance can only be roughly stated as over 500 
years. At the foot of the table are the figures for a few stars invisible to the naked eye. 
The velocity of ‘“‘the runaway star,’’ Groombridge 1830 (a faint star in Ursa Major), 
is Over 200 miles a second, or over 720,000 miles an hour. No explanation of such phe- 
nomena is yet at hand. Most of the stars show traces of association into groups, different 
groups betraying a common drift. 

We now know that the stars, instead of being really ‘‘fixed,’’ have motions of their 
own, relative to our own position in space. The motions of a star may be defined, in the 
terms of its annual displacement on the celestial sphere, in seconds of are. This is usually 
called its proper motion, see the column marked P. M. Or when expressed as a velocity 
in miles per second it has been called the star’s ‘‘Cross Motion.’’ ‘This is indicated in the 
column marked C. M. To secure the velocity per minute multiply of course by 60. But 
the stars have another motion also—a motion that represents no displacement on the 
celestial sphere, for it is 7m the line of sight. This linear motion is indicated in the terms of 
velocity in miles per second in the column R. V. (=radial velocity). When the star is 

138 


Distances and Velocities 139 


approaching our system, decreasing the distance at the velocity indicated, the minus sign 
accompanies the figure; where the star is receding from us and the distance is increasing, 
the indicated velocity is preceded by the siga plus (+). Stars enclosed in brackets [ |] 
are visible only from extreme southern latitudes. 


TABLE A. STAR DISTANCES AND STAR MOTIONS 





























Mag. The Star 12 1D: F 12) MAL C.M Ine YS 
Ouimlientoka() or Centaurus). oo. fsse.n ses ote 0”.759 4.3 A 3”.66 14.2 SU 
Sto oiiis—=Alpha (a) of Canis Major... . 022... 376 Sa A ee OE) | —5 
Peta FOr, COIS 4.060. wk cae we dias anak segue 9.8 B 17093 17.0 
0.5 |Procyon=Alpha (a) of Canis Minor........... 224 10.1 B i” 25 Dies =2.5 
PI TRE ITILS os ois dep a de Wa ie els Boom ves bad os sehr 10.5 A Sai 49.6 — 39 
9 Altair —=Alpha (a) of Aquila.......5.........-. 238 Tea B 65 8.0 — 20.5 
eet aan) Of Cassiopeia. «05. 2a odes ee ce eee wee 201 16.2 B 1.25 18.2 +5.6 
Mrommemne wor Ursa Major: ie. vase. ck ca de eee nae .179 18.2 ¢ 78 12.0 
ese Omiieron(O2) Of EridanuSeet oes 196s soe us ney fl 18.8 B 4” .08 69.0 
eee erat) of Hercules. .... 2.0/0.5 ie eae .142 Pee) B 61 | 12.6 
Walivitre— Oiaicron (O)'or Cetus...4.. deo. esos 142 22.9 B 2 eden +40.4 
1.3 |Fomalhaut = Alpha (a) of Piscis Austrinus..... ales 23.6 B a7 7.9 
Brenenepola = Beta (B) of Leos .s. ieee ees .129 25.3 Cc 51 11.6 
ee TP Ol VATCO aati db ved Kad eda aed os 118 27.6 Cc ifs) 19.6 225 
Meu Whol CASSIOPCLaas cia + 4 oss 5 ae ciel >, oe ees ite 2001 B Beers 98.2 — GO 
eA Ccatmiian cy wOl TACO. ss 665056 seks 0s ss ee en .107 30.5 G 02 0.7 — 16.8 
Bem MUN ROL ELErCules... sa ssas soe sacle ene ves .106 30.8 Cc Shigh || Beis =0),8 
rae AMOITICU CY) Ol CY ENUS: Vie. Geos aio bane s eee ee .106 30.8 | xe 003 0.08 Tied, 
Onley eear—enlona (Ol )LOn Iytalces ats lon aes ca aie = e .094 BAe B 35 10.9 — 0.3 
ee metera (ONrOt Ursa MAIO... co. is. dead es cers cy 092 35.5 Cc 1”.09 34.8 +9.3 
0.2) |Arcturus = Alpha (a) of Bodtes..........6.... 075 43.5 A 2323 89.3 == 3D 
meaaieta ls) OF CASSIOPCla... <6... cae ee ee es oe .074 44.1 B 56 BOD. | 
2.1 |Ras Alhague=Alpha (@) of Ophiuchus........ .074 44.1 B 26 10.3 
fim ldeparan = Alpha (a) of Taurus.............. .073 44.7 B 20 8.0 +34.2 
On Capella—Alphai(a) ai Auriva sya... ..90-50. 45 .066 49.4 B 44 19.6 +18.6 
bem olux— Beta (B) of Gemini... 00.00. 064 50.9 B 62 28.4 +1.9 
mermaid Y)Ol Virgo wo. sas. awe wee ee vce ss .058 56.2 B 55 27.8 — 2.0 
permet (@) Ol Crux)... fat ceage pisses eas bes 055 59.3 B .06 2.2 
0.6 |[Achernar = Alpha (a) of Eridanus]............ .O51 64.0 B .09 5.2 
2.1 |Polaris=Alpha (a) of Ursa Minor............. .047 69.4 B 04 2.5 
Cemieerpy on Centaurus).c cc... cos ode Pes we ans .037 88.1 B .O4 aD 
ro yreguius Alpha (a) of Leo... 22.6.3. -.0 00s .033 99 B i Z2ee 
Boaivisgar== Zeta (f) ot Ursa Major... .. oe eee u 033 99 A 13 11.5 oid 
V |Betelgeuze = Alpha (a) of Orion.............. .030 109 B .03 2.9 
1.2 |Antares = Alpha (@) of Scorpius.............. 02 112 B 03 3.0 <0 
Tomeasvor=Alpna (a?) of Gemini ..5.. 24.26.05. .028 116 B 2011) €20.9 +3.7 
Pree eta) Go-COTux |. 2 foes. iG Pe auc ees weet 008 408 B .06 22.0 
2.2 |Alamak=Gamma (y) of Andromeda.......... .007 466 B .07 29.4 — 6.8 
Gm ice! = Beta (B) of Orion. o. cc. sce ese ee .007 466 B .00 0. 
—o.9g [Canopus = Alpha (a) of Carina (Argo Navis)].. .007 466 B .02 8.4 +12.4 
ie arsellattix =Gamma (y) of Orion... 2.00... 5%. — .003 500+ A .02 
mem Dene — Alona (ce) of Cyonus: «cea. acess — .004 500+ A .004 
Wemopica—=Aipha (a) of Virgo. ....2.5.2a0000e0. ele 500+ A 05 +1.2 
3.1 |Albireo = Beta (B) of Cygnus.................| — .021 500+ A or —14.9 
7.6 |Lalande 21, 185 (R.A. Xh. 57.9m.; D.+36° 38’) 403 8.1 A 4.77 34.9 
8.2 |Groombridge 34 (R. A. Oh. 12.5m.; D.+43° 27’) 281 11.6 A 2.85 29.8 
8.9 |Lalande 21, 258 (R. A. XIh.0.5m.; D.+44° 2’). .203 16.1 B 4.46 64.8 
6.5 |Groombridge 1830 (R. A. XIh. 47.2m.; D.+38° 
CASE oe A git SNe ree ee te a ee eee 102 32.0 B 7.07 |204.3 —58.9 


























140 


H Beginner’s StareBook 


A list is here given of the seventy brightest stars, indicating their magnitudes according 


to the Revised Harvard Photometry (1908) in the column marked H; and according to the 
determinations of the Astrophysical Observatory, Potsdam, in the column marked P, as 
In both H and P the figure is here 


shown in the Sternverzeichnis of Ambronn, 


1907. 


TABLE B. STAR MAGNITUDES 























No. Star Il ig: B No. | Star H 12) B 
I Sirius =Alpha (a) of Canis 35 Jbl (AG rose Opakopak 525 a4 ha An oc 1.9 0.44 
Maj Orie fly eee rae cet eee [==.6 10.76 || 36 Alhena=Gamma_ (y) of 
2 [Canopus =Alpha (a) of Ca-| Gemini, ioe eae 1.9 2.3| 0.44 
Tinta | sees Sato Oso) Filey: Dubhe=Alpha (a) of Ursa 
3 [Alpha (a) of Centaurus].... 0.1 2.29 Majorca oe 2.0 2.0] 0.40 
4 Vega=Alpha (a) of Lyra....| 0.1 Oh | DLO. ||) BE Epsilon (€) of Sagittarius...| 2.0 0.40 
5 Capella=Alpha (a) of Au- 39 Wezen=Lelta (8) of Canis 
TIS Pe LA rere ee ©.23) §0.5 4) 2.09 Majoreino. cee eee 2.0 0.40 
6 |!Arcturus=Alpha (a) of Bo- 40 Beta (B) of Canis Major..... 2.0 0.40 
OES. eee eee eee eee 0.2 0.3; 2-09 || 41 [Delta (8) of Vela]... .-e eee 0.40 
7 | Rigel=Beta (B) of Orion....| 0.3 1.91 || 42 Theta (®) of Scorpius....... 2.0 0.40 
8 Procyon =Alpha (a) of Ca- 43 Menkalinan=Beta (B) of 
nis Minor.....:......... 0.5| 08] 1.59 AMLTIGS sto as 2 nde once 21 2) 20236 
9  |{Achernar=Alpha (a) of 44 | Polaris=Alpha (a) of Ursa 
Eridanus). s-eaa aes 0.6 T.44 MUnOT: got nae eee ent 2.3 0.36 
10 [Beta (B) of Centaurus]. 0.9 1.10. || 45 [Alpha (a) of Pavo].. 2.5 0.36 
II Altair = Alpha (a) of eaiey 0.9] 1.2] 1.10 || 46 Ras Alhague = Ripie (a) of 
12 Betelgeuze=Alpha (a) of Ophitiehtisten ee teen Pil 2.5| 0.36 
Onin. a ene 0.9 1.10 || 47 Sigma (©) of Sagittarius..... Dri 0.36 
10) (Atoirai(a)hot Grr] eee Tl 0.91 48 Algol=Beta (B) of Perseus, 
14 Aldebaran=Alpha (a) of WES sibs ete Oe Coe eee Di 2.30220 
Laurus scene eee ea 1.2] 0.91 || 49 Alpheratz = Alpha (@) of An- 
15 | Pollux=Beta (B) of Gemini} 1.2) 1.5] 0.83 dromeda. Syne. 4 eee 2.2) “Sooo. 
16 |Spica=Alpha (a) of Virgo.. 12 0.83 50 [Al piai(a)iohtGrtts|/ Seen 2D 0.33 
17, Antares = Alpha (a) of Scor- 51 Alphard=Alpha (a) of Hy- 
Pits cee eee ae tee Ae Te 0.83 dra, Jae ee ts a ee aie, 2:25 Onss 
18 Fomalhaut=Alpha (a) of 52 Mizar=Zeta (f£) of Ursa 
Piscis:Austrious 2.00 year 133 0.76 MajOrssatua.cicemee: cae 22 2:4) 0:33 
19 Deneb=Alpha (a) of Cyg- 53 Saiph = Kappa (k) of Orion. .| 2.2 0.33 
TUISs2o hs See eRe eee Tes ee On O70 54 Alamak =Gamma () « of An- 
20 Regulus=Alpha (a) of Leo.| 1.3 Tesi 047.6 dromeda. . 2.2 Pri, || ORS 
21 [Beta (B) or Grix ieee pee is 0.63 || 55 [Lambda (A) as Vela] nS cea a2 0.33 
22 Castor =Alpha (a) of Gem- 56 [Ganomar(y) ion Vela Dye 0.33 
inl. ; ote ana ee etsy 1.6/ 2.0/ 0.58 || 57. | Denebola=Beta (B) ofLeo..| 2.2} 2.6| 0.33 
23 [Gamma (y) of Crux]....... 1.6 0.58 || 58 Hamal = Alpha (a) of Aries..| 2.2 2 2aOne 
24 Epsilon (€) of Canis Major.| 1.6 0.58 || 59 Deneb Kaitos=Beta (B) of 
25 Alioth =Epsilon (€) of Ursa Celusyeeaiepemocrc rer re 22 0.33 
ML BiON Sane ree ee ee ite D2 OS 2 60 Kochab =Beta (B) of Ursa 
26 Bellatrix=Gamma (y) of Minor ait e eens De?) 2334) 20.33 
OPOn Ae ean ee a ae oe We7) Zeta Ons 2 61 [Beta (B) of Grus].......... 2.2 0.33 
27 |Lefath=Lambda (A) of A 62 | Alpha (a) of Cassiopeia, max.| 2.2} 2.3] 0.33 
as ae aes ot nes ieee ate Abe 63 [Iota (+) of Carina]. . en 0.30 
a Ai Eine Oe 64 Gamma (y) of Cams a De 2.5 o 
1012 +. oR ee nk ae 1.8 0.48 65 [Theta (8) of Centaurus]. . see pees 
30 Nath = Beta (f) of Taurus... 1.8 2.0] 0.48 66 [Zeta (£) of Puppis]. . 2.3 9-39 
: 67 Gemma=Alpha (a) Be ie 
3! [Beta (B) of Carina]........ ie 0.48 ROA) IBYORREM Sn Gg 46 Hoos OL 3) 2 OOO 
3? pe eect i res es 1.9 0.44 68 Gamma (y) of Cygnus...... aoa 251), 0:80 
33 Algenib=Alpha (a) of Per- 69 Epsilon (€) of Scorpius...... 2.4 0.28 
Sets fe a eee teen 8 1.9| 2.2] 044 || 70 |Mirach=Beta (8) of An- 
34 Benetnasch=Eta (mn) of CrOmeda sn cota a wie 2.4) asa Onee 
|Opecteh. IMME WON oo oon doen 6 vie) 2.3| 0.44 





























Relative Brilliancp 141 


carried to only one decimal, fractions over .05 counting as .1. For example, the precise 
mag. of Sirius is —1I.58. Stars south of the celestial equator were not included in the 
Potsdam determinations. 

In the column marked B is indicated the relative brilliancy of a number of the stars on 
a simple decimal scale, assuming Aldebaran—the Alpha (a) of Taurus—as approximately 
a first-magnitude star. No star is precisely of mag. 1.0. By this method it may be seen 
at a glance that Sirius is more than 10 times as bright as a standard first-magnitude, that 
Capella is more than twice as bright as such a star, and that Epsilon (¢) in Ursa Major, the 
third star from the tip in the Dipper’s handle, is about half as bright. These decimal 
notations are based on the magnitudes as shown in column H. 

The system of notation just described is far simpler than the comparison of stars by 
““magnitudes,’’ for in the scale of magnitudes the beginner is confused by the occurrence of 
zero magnitudes and negative (= minus) magnitudes, these notations applying to some of 
the brightest and most interesting stars. A 2d-magnitude star is about 2.51 times fainter 
than a first-magnitude, a 3d-mag. star is about 2.51 times fainter than a 2d-magnitude, etc. 
The scale, even in this direction, is confusing, because the brilliancy of the star does not 
increase with the increase of the numeral of magnitude, but the reverse. Yet in the other 
direction the conventional scale becomes still more troublesome, for as Aldebaran and 
Altair are approximately of the first magnitude, there is no way to indicate stars brighter 
than these, except by resorting to decimals of unity. We have been forced, therefore, to 
describe Vega as mag. 0.1, Arcturus as mag. 0.2, and Sirius as lower in magnitude than 
zero, or of mag. minus, — 1.6. And this is the brightest star in the sky! Among the techni- 
calities of a really noble science this system is, in the judgment of the plain man, one 
of the “puzzles” of astronomy. As current text-books and monographs all assume the 
traditional photometric scale, the maps, etc., of this book have been composed in accordance 
with it. The beginner will find that the slight variations between the Harvard and Pots- 
dam results are chiefly due to the factor of color in the light of the stars. The Harvard 
results are usually accepted as standard in England and the United States. The first twenty 
of the seventy stars in the column marked H are generally classified as of the “‘first magni- 
tude”; the remaining fifty, with some ten others, are of the ‘‘second magnitude.”’ 

We have seen that the individual stars are often designated by the Greek letter, used 
with the Latin genitive of the constellation name; see p. 12, second footnote. For readers 
who do not know Latin, some of these genitive forms that are less easily recognized are here 
given in italics:—Aries, Ariétis; Cancer, Cancri; Cétus, Cett; Cygnus, Cygni; Draco, Dra- 
coms; Gemini, Geminorum, Leo, Leénis; Lepus, Lepéris; Libra, Librae; Orion, Oridnis ; Per- 
seus, Persei ; Serpens, Serpentis; Taurus, Tauri; Ursa Major, Ursae Majoris ; Virgo, Virginis. 


SOME VARIABLE STARS 


Many of the stars show marked changes in brilliancy, varying in magnitude. These 
variations are in many cases periodic, and in some instances we have been able to ascertain 
the causes of change; see p. 13. In other cases no adequate explanation of these changes in 
brightness has been found. A few of the best known are given in this list. Those marked 
S. B. are also spectroscopic binaries, their periods of variation corresponding to their 
periods of revolution. This may indicate that at minimum one component (as the stars 
revolve round their common centre of gravity) passes behind the other and is totally or 
partially eclipsed. The magnitude of each variable star at its maximum and at its 
minimum is indicated in the table below; and, in the column marked P, is indicated the 


142 El Beginner’s StarzBook 


period of variability in Days. The smaller variables are usually given, for symbols, the 
Arabic capitals in the order of their discovery in each constellation,—as R Leporis. For this 
use of the Latin genitive, see p. 141; also see second footnote on p. 12. 


TABLE C. SOME WELL-KNOWN VARIABLES 












































Star | Max. | Min. 12 Star Max. | Min. 122. 
Eta (n) of Aquila (S. B.)...... aha) 4.5 7.18 Ras Algethi=Alpha (a) of 
: Hercules (sane eee ee aon 3.9 
[Eta (yn) of Argo (Carina)]..... I 7.4. 
: d Rot Lepus janetc hee 6.1 9.7 436.1 
Epsilon (€) of Auriga (S. B.)...| 3.4 AI 9905. 
+GAe Deltal(@)ion Libra(S: Be eee 4.8 6.2 2.33 
Alpha («) of Cassiopeia....... DP? 2.8 
Totay(U) of Uilbral essen 4.3 Se 
Delta (8) of Cepheus (S. B.)...] 3.7 4.6 5.37 
Sheliak=Beta (8) of Lyra 
Mu (p) of Cepheus........:.. 4.2 | 5.? (S..B.) teat ee een ae 3 feae ded 12.9 
Mira =Omicron (0) of Cetus...| 1.7 9.6 331.6 Betelgeuze = Alpha (@) of Orion| 0.9 1.4 
Chi (x) of Cygatisyaass oes A. 13.5 406. Algol=Beta (B) of Perseus 
Eta (yn) of Gemini (S. B.)....2.) 93.2 4.2 231.4 (S- B.).. cass as ee eines: sits 3-2 ot 
Zeta (£) of Gemini (S. B.)..... 2a 4.3 10.15 Rho (p) of Perseus........... 3-4 Ave 
Lambda‘(A) of Taurus (S. B.).2) 33235 | 4. 





SOME BINARY SYSTEMS 


As already explained, pp. 12 and 117, many of the double stars represent two suns in 
revolution about a common centre of gravity. In some cases their orbits have been calcu- 
lated, and the periods of revolution are known with a fair degree of accuracy. In this table, 
the combined magnitude of the components is indicated in the column marked Mag.; the 
individual mag. of the components in the col. marked M. of Comp., and their period of 
revolution, in Years, is shown in the col. marked P. At the close of the table are added a 
few important binaries with long periods. The longer the period, the larger the probability 
of error. In some cases, like that of Gamma (y) of Leo, the period is so long and so uncer- 
tain that it has seemed best not to include them here. 


TABLE D. ‘TELESCOPIC BINARIES 


























Mag. Star 2). M. of Comp. || Mag. Star P. |M.of Comp. 
4.3 |Kappa (k) of Pegasus......| 11.4 4.3, 5.5 3.9 |X1.(€) of Ursaavajor. .. «ou 4.4, 4.9 
3-5 |Epsilon (€) of Hydra......| 15.7 a SOe anal 3.9 |Gamma (y) of Corona Bore- 

3.7 |Beta (B) of Delphinus...... 27.7 4.0, 6.1 DNS ie are ee ee at 
BO Zee eyotiiorch ee a ee epee ee 0.1 |Alpha (a) of Centaurus....| 81.2 Oey Udi 
So Rie ee Come hoes Mee sry ion A.D e} 70.01 Ophitichuce a see 88.4 FBG, 
Fes rel nsdeesticn 8 ee Hees: A.6. 51 (E) Of Bootes en. oe 148.5 4.8, 6.8 
Sri 6 isitue= Aisha way Gane 4.5 |Omicron (0?) of Eridanus..| 180.0 A Seoul 
Ul Wferment «pra arose eaaore ey: 48.8 | —1.6, 8.4 2.9 \Gamma: (y) of Virgoren. a 194.0 3 eee 
2.2 |Alamak=Gamma (y) of 4.3 |Mu (p?) of Bodtes.........| 275.8 A: 5,0Os74 
Andromedaay eae ieee 55. Deore Sel 


3.6 |Eta (m) of Cassiopeia...... 327.9 erie Vide 
4.6 | lad (rob Cyomae can... eel ems ies 4.0, 8 see 
| 1.6 |Castor=Alpha(a)ofGemini) 346.8 2.020 


Av7 Zeta on Cancers eer Mees ONL 5.0, 5.7 


























Suggestions for Work 143 


These are binary systems discovered by means of the spectroscope, the component 
suns being so near together that it has been impossible to effect their division with the 
telescope; see p. 117. The periods of revolution are indicated in Days in the col. marked D. 
At the close of the table I have listed a number of important stars thought to be spectro- 
scopic binaries but the periods of which have not yet (1912) been determined. 


A Frew SPECTROSCOPIC BINARIES. TABLE E 


























Mag. Star Period in Mag. Star Period in 
Days. | Days. 
it at 
2.2 |Alpheratz=Alpha (@) of Androm- 2.5 |\Mintaka = Delta (8) of Orion. ..... 7fe 
28! he elo Gita RR NOC ek eee Hear 96.7 : 
ZO LOved (b).Ol OLION. a. secant asta ee 4 29.14 
Peter eran 0) of Aquila... i... es. ews 7.02 
V |Algol = Beta (8) of Perseus........ 2.87 
Wa detann ot Aquila... v4. sa ses os : 7.18 
1.2 |Antares=Alpha (@) of Scorpius.... 2120. 
Bem berap) Of Aries. oi... i. ace eh 107.0 
BEOn Clan Gola ait Saeeaeny rs leaeocienn ee 138. 
0.2 | Capella =Alpha (a) of Auriga...... 104. . 
| 2.4 {Merak=Beta (8) of Ursa Major.... 27.16 
Demet) OF AUTO. c68 ye we cae 2:00 14 | : 4 
| 2.2 |Mizar=Zeta (€) of Ursa Major..... 20.54 
moa peeta (p) of Capricormius...i..4...7. [e75. : 
2.1 | Polaris = Alpha (a) of Ursa Minor. . SrOr7 
—o.9 |Canopus =Alpha (@) of Carina..... 6.74 ; : 
ayer en A | SOCEM olay, (CH) he Wangeteys 5 og 50084 4.01 
.3 | Alphirk = Beta Of Gepneis anne 0.1 
eran ©) r ? 1.7 | Lefath = Lambda (A) of Scorpius... 5.6 
Win@ettan(o) of Cepheus: ... 2.65. 006. 537 . ; 
2 -Oube( por Canis Marjory, wn... tes 0.25 
2.3 |Gemma = Alpha (@) of Corona i P 
TOUS OILIGS <3 a is aia i ieee ae 17.36 V | Betelgeuze = Alpha (@) of Orion.... 
3.6 | Thuban =Alpha (@) of Draco...... 51.38 1.3 | Deneb=Alpha (a) of Cygnus...... 
2.9 | Castor =Alpha (a') of Gemini..... 2.03 1.7 | Alioth = Epsilon (€) of Ursa Major. . 
2.0 Alpha (a2) of Gemini..... 9.22 1.7 | Bellatrix =Gamma (y) of Orion.... 
V |Mekbuda=Zeta (€) of Gemini..... 10.15 1.8 | Alnilam = Epsilon (€) of Orion...... 
2 Seviseta (B) of Herctiles.....0.:...... 410.6 1.9 | Algenib=Alpha (@) of Perseus..... 
ArOmmapsiion(€)ror Elerciles 0... ae. 4.01 1.9 |Gamma (y) of Gemini............ 
Wanbetiano) of Libray... 5 6. ne ee ee 2aa3 2.0 | Dubhe=Alpha (@) of Ursa Major... 
V |Sheliak = Beta (B) of Lyra......... 12.91 5.6 |61" and 62? of Cygnus............. 














O34) | Rigel = Beta (B) of Orion.:........ 21.9 4.. |Alcor (g) of Ursa Major........... 





USEFUL WORK FOR THE AMATEUR 


Facing the preface of this book are two quotations from Dr. George E. Hale of the Mt. 
Wilson Solar Observatory, in reference to the useful work which may be accomplished by 
the amateur. Dr. Hale has special reference to the spectroscope. So broad, however, is 
his suggestion that it is quite as applicable to the telescope. Indeed it is usually through 
the elementary preparation afforded by the telescope that the beginner advances to the use 
of the spectroscope itself. 

The amateur observer who may wish to attempt some useful work, may take up: (1) 
the study of variable stars; or (2) the careful systematic search for comets; or (3) the 
observation of the surface markings of the planets; or (4) the study of double stars; or (5) 
the drawing and recording of sun-spots; or (6) the making of careful records as to meteors 
and meteor trails, or other unusual phenomena that may come under observation. Records 


144 fH Beginner’s StareBook 


made at the time are often of special value. Fully to deal with these various interests would 
require the preparation of another volume. 

One of the most fruitful fields for amateur effort is the first named—that of variable 
stars. After becoming fairly familiar with the constellations and with the ordinary use 
of the telescope, the amateur who wishes to aid in the observation of variables should enter 
into correspondence with a working observatory. That of Harvard College, Cambridge, 
Mass., is one of a number of institutions giving direction to amateurs in the study of 
variables. Letters addressed simply to the ‘‘ Director”’ of the Observatory will be referred 
by him to the proper secretary. 

Reference has already been made to the search for comets. In such work, one must be 
in patience persistent and in persistence patient! But any amateur who regularly sweeps 
with his telescope any definitely selected portion of the sky at intervals of a few days is not 
unlikely to be rewarded by the finding of a comet. First, however, he should learn what 
the smaller comets look like, and how they behave, by following some of those which are 
frequently reported in the astronomical journals. Upon findinga comet, the fact, with the 
approximate position of the object in R. A. and D. (see note 14, p. 32), should be at once 
communicated, for verification, to an observatory. 

As to double-stars, the contrasts of color may usually be studied with greater accuracy 
in a reflector than in a refractor, and yet even such small refractors as are noted in this book 
may prove useful. The focal length of the objective should, however, be long enough for 
great refinement of definition, and the eyepieces should be carefully corrected for color. 
Cheaper instruments may not show colors so accurately, but they may aid the eye in learn- 
ing to estimate the magnitudes of the telescopic components of the easier doubles. First 
make a list of the doubles to be observed, trying not to note the magnitudes of the compan- 
ion stars. Then observe, and record your estimates of the magnitudes of both components, 
and afterward compare your estimates with the magnitudes as given in the Observer’s 
Catalogue. This will gradually provide a training to the eye in estimating the magnitudes 
of telescopic objects, a training highly serviceable in the study of variables. 

It is chiefly important to remember that any work that interests the observer and 
which he is willing to do deliberately and carefully is likely to be of ultimate service to 
science. No matter how “‘useless”’ it may be called, such labor must result in the educa- 
tion of the amateur in habits of observation,—in accuracy, precision, and mental force. 
As these capacities increase, new interests and opportunities will open out. Things that 
are worth doing are frequently brought to the observer’s attention in the pages of our 
popular astronomical periodicals. A journal like Popular Astronomy, noted on p. 146, is 
often most helpful with suggestions. 


A List oF Booxs 


Whether or not the beginner desires to give interest and time to scientific work, there 
will be the need for further information. This volume has not attempted to fill the place of 
a text-book on astronomy, and therefore the questions of how and why will demand further 
attention. Fuller and more technical manuals for the telescope will also be desirable, as 
well as a star-atlas and a planisphere. A few volumes on the general history of astronomy 
and on special subjects may be added, according to the need or interest of the student. 

Some of the best of the general text-books are: (1) A Popular Astronomy, by the late 
Simon Newcomb, Director of the U. S. Naval Observatory, Washington; American Book 
Co., N. York. Not kept up to date as to recent developments but peculiarly able and 


Some Usetul Books 145 


lucid in its expositions.* (2) Elementary Lessons in Astronomy, by Sir Norman Lockyer; 
London, Macmillan & Co. Clearly and vividly written. (3) A New Astronomy, by Prof. 
David Todd; the American Book Co., N. York. Rich in illustrative experiments. (4) 
The Family of the Sun, by E. S. Holden; published by D. Appleton & Co., N. York 
and London. (5) Descriptive Astronomy; by H. A. Howe, Director of the Chamberlin 
Obs.; Silver, Burdett & Co., Boston and N. York. (6) A Manual of Astronomy, by the 
late C. A. Young, of Princeton University; Ginn & Co., N. York and Boston. A little 
difficult for the beginner, but a thoroughly well-wrought book,—perhaps the best general 
statement of the whole subject available at this time (1912) in English. 

Among the simpler volumes, of value in learning the constellations, may be mentioned: 
(1) A Field Book of the Stars, by William Tyler Olcott; G. P. Putnam’s Sons, N. York & 
London; (2) Astronomy with an Opera-Glass, by Garrett P. Serviss; D. Appleton & Co., 
N. York; (3) Half-Hours with the Stars, by R. A. Proctor; G. P. Putnam’s Sons, N. York 
and London; (4) Flammarion’s Astronomy for Amateurs; English translation pub. by D. 
Appleton & Co., N. York. An admirable first-book in its field is The Spectroscope and its 
Work, by H. F. Newall, M.A., Prof. of Astrophysics in the University of Cambridge, 
England; pub. by the 8. P. C. K., London, and by E. Gorham, N. York. 

Among the more satisfactory star atlases are: (1) the Stern Atlas of J. Messer, pub. by 
K. L. Ricker, Leipzig; to be had of G. E. Stechert & Co., N. York and London. The two 
maps at the close of this volume were suggested by Messer’s final plates, but they have been 
entirely redrawn by hand, the scale reduced, and the star magnitudes brought into harmony 
with the latest determinations. (2) The Himmel Atlas of Schurig, new edition 1910, is less 
expensive—costing less than $1.00—and is attractive and adequate. There is so little 
text to Schurig’s Atlas that translation is hardly necessary. (3) The Star Atlas of Klein is 
supplied with full descriptions of telescopic objects. These are translated by McClure for 
the English edition, of which the Society for Promoting Christian Knowledge is publisher, 
New York and London. (4) The New Star Atlas, by R. A. Proctor, is supplied with no 
descriptive matter, but it is small in size as well as convenient and accurate; Longmans 
Green & Co., N. York and London. (5) A Popular Guide to the Heavens, by Sir Robert 
Ball, contains a star atlas as well as an atlas of the moon, together with much illustrative 
material; more expensive than any of the preceding. Pub. by Philip & Son, London, 
and tne . Van Nostrand Co., N. York. 

Among books especially written for larger instruments I would heartily commend: (1) 
Celestial Objects for Common Telescopes, by the Rev. T. W. Webb, F.R.A.S.; Longmans 
Green & Co., N. York and London. The beginner, just at the first, will find it too full for 
his uses, but it will soon prove indispensable. It covers the subjects of Sun, moon, planets, 
etc., as well as the stars. Webb’s map of the moon is especially clear and full. A very 
satisfactory map of the moon will also be found in The Moon, by T. G. Elger; pub. by 
Philip, London; and the D. Van Nostrand Co., N. York. (2) On the stars, star-clusters, 
nebule, etc.,—but not the objects of the solar system,—see also, the Cycle of Celestial 
Objects, by Smyth and Chambers; The Oxford Press, N. York and London. In addition 





t Its high qualities were early recognized in Germany, where the volume was translated by Engelmann, and has 
been successively edited and enlarged by Vogel and Kempf of the Royal Observatory, Potsdam, and certain asso- 
ciates of the highest standing. This German volume, known as the Populdre Astronomie of Newcomb-Engelmann is 
now (1912) in its fourth edition. It is three or four times the size of Newcomb’s original book, and fully illustrated, 
Despite some defects, it ison the whole the very best exposition and exhibit of the present state of astronomical science 
—admirable in itself, and a generous tribute to America’s greatest astronomer. Iam largely indebted to this volume 
for the material in the table of Spectroscopic Binaries here given. To be had, as yet, only in German; of G. E, 
Stechert & Co., N. Y.and London. Published by W. Engelmann, Leipzig. 


146 El Beginner’s StareBook 


to my many obligations to the books named above, I would also mention an admirable 
volume by James Baikie, F.R.A.S., called Through the Telescope; pub. by A. and C. Black, 
London. Fowler’s Popular Telescopic Astronomy; T. Whittaker, N. York; the Amateur 
Telescopist's Handbook, by F. M. Gibson, and Noble’s Hours with a Three-inch Telescope; 
the last two pub. by Longmans, may also be mentioned here. I have expressed my chief 
acknowledgments in the preface to the present volume. Among the best general books on 
the subject for the serious modern reader are the volumes by the late Miss Agnes M. Clerke 
—The System of the Stars, second edition much revised; and the History of Astronony 
in the Nineteenth Century, and Problems in Astrophysics,—all pub. by A. & C. Black. In 
scholarship and in general intellectual power Miss Clerke has taken rank among the leading 
women of the nineteenth century. On the poetry and mythology of the stars there is a 
charming and inexpensive little volume by Dr. J. G. Porter, The Stars in Song and Legend, 
with illustrations from the drawings of Albrecht Durer; pub. by Ginn & Co., N. York and 
London. The national Ephemerts is indispensable; see footnote on page 82. 

The beginner should early learn to use all his authorities with discrimination. The 
literature of astronomy abounds in detail; error is therefore inevitable. Prof. Young, of 
Princeton University, praised astronomy as a training in accuracy, yet obvious inaccuracies 
appear in his own books—and Prof. Young’s books are as accurate as any that exist. No 
atlas more accurate than Klein’s is published, yet the star Delta (¢) in the well-known 
Dipper is given the fourth magnitude in Plate I, and the third magnitude in Plates III and 
IV. Schurig’s useful atlas, among other errors, marks the great nebula of Andromeda as 
M. 31 in Tab. III, and as 33 in Tab. I. The latter is the Flamsteed number, but incon- 
sistent usage leads to much confusion. Many errors also arise from the fact that new 
information has made old figures, or old tables, obsolete. It is therefore important to note 
the date of the book consulted as well as to note the nature of the authorities quoted. That 
absolute freedom from error has been attained in the present volume the author cannot 
hope,—though all possible care has been exercised. I can only say that such errors as may 
be pointed out to me will be promptly and gratefully corrected in future editions. 

One or two good astronomical journals will be found useful,—such as The Observatory, 
published at Greenwich, England; or Popular Astronomy, published at Northfield, Minn., 
U.S.A. Among continental periodicals are Sirius, in German, published at Berlin,—G. E. 
Stechert & Co., N. York and London, through whom may be obtained also the monthly 
Bulletin of the Société Astronomique de France. 

A planisphere is a useful device for quickly showing what stars are above the horizon 
at any particular hour. Among these are Philips’ Planisphere; Whittaker’s Planisphere; 
and one called the Barritt and Serviss Planisphere and Planet Finder. The last is about $5; 
the two others are sold at retail at less than $1.00. The present volume, if reference be 
made to p. 35, will serve—approximately—the purposes of a planisphere, as well as a planet 
finder (p. 82 fol.), for the evening hours of any year. Moreover, while the telescopic 
objects are seldom indicated in a planisphere, most of the easier objects are here included. 
As the Night-Charts are especially intended for the unaided eyes, the merely telescopic 
clusters and nebulae are usually shown only in the Key-Maps. For determining with. 
greater precision the time of the rising and setting of the stars, a good planisphere is, 
of course, invaluable. 


Inder 


Names of the Constellations and the brighter stars will be found in the Observer’s Catalogue, pp. 116-136, in 
their alphabetical order, with indication of the maps in which they occur as objects for observation in the evening 
sky. Use Observer’s Catalogue, therefore, as Index for stellar objects. 

Names of the Planets with tables showing the approximate positions of Venus, Mars, Jupiter, and Saturn for 
each month will be found on pp. 82, 84, 86 fol. 

A Time-Schedule showing the appropriate Night-Charts and Key-Maps for the evening hours of any day in 


any year will be found on p. 35. 
A 


Abbott, C. G., 68 

Alphonsus, lunar form., 76 

Alps, lunar mts., 71, 77 

Altair—Diagram, 28, 119 

Alt-azimuth mountings, 103, 106, 
107 

Amateurs, work for, 143 fol. 

Ambronn, L., pref., 116, 140 

Andromeda, great nebula in, 21, 118 

Andromedes, meteors, 96 

Apennines, lunar mts., 71, 77 

Apex of Sun’s Way, 66 

Aquarids, meteors, 96 

Archimedes, lunar form., 76 

Aristarchus, lunar form., 71 

Aristotle, lunar form., 74 

Arnold, Matthew, quoted, 7 

Asteroids, or planetoids, 81 

Astronomy, 2 

Atlas, lunar form., 74 


B 


Baikie, James, 146 

Ball, Sir Robt., 121, 145 

Bayer, J. (1572-1625), 12 

Bernouilli, lunar form., 73 

Bessel, F. W. (1784-1846), German 
Astr., 124, 138 

Binaries, Spectroscopic, I2, 117, 143 

Binary Stars, 12, 117, 142 

Binocular, prism-, 3, 98, 99 

Boss, L., Am. Astr., 66 

Bryant, W. W., quoted, 135 

Bullialdus, lunar form., 77 

Burckhardt, lunar form., 73 

Burnham, S. W., Am. Astr., pref. 


C 


Campbell, W. W., 63 
Capricornus—Diagram, 28 
Carlyle, T., quoted, 2 
Carpathian mts., lunar form., 77 
Cassini’s division, 91 
Castor, 12, 125 
Catharina, lunar form., 75 
Caucasus mts., lunar form., 71 
Centaurus, Alpha of, 9, 123 
Chambers, G. F., 107, 145 
Clavius, lunar form., 76 
Cleomedes, lunar form., 72 
Clerke, A. M., 16, 146 
Clouds, Sea of, lunar form., 71 





Clusters, Star-, 17 

Comets, 29, 92, 93, 94, 95, 137 
Conflicts, Sea of, lunar form., 71, 72 
Constellations, early, 118 
Copernicus, lunar form., 71, 77 
Corona of Sun, 63, 67 
Corvus-Spica—Diagram, 26, I17 
“Craters,’’ lunar, footnote to 71 
Cristum, Mare, 71, 72 

Cross, Northern and Southern, 124 
Cyrillus, lunar form., 75 


D 


Declination, 12; note 14, p. 32 

Dipper, Great, 22; col: 1, p. 38, 134 

Dipper, Little, col. 1, p. 38, 135 

Distances of stars, 9, 138; of Sun, 
68; of Moon, 69 

Distortion in maps, 4, 30 

Dog-Star, 122 

Double-stars, 12, 116 fol. 


E 


Earth, earth-shine, 69 

Eclipses of Sun, 63, 68 

Ecliptic, 80, 81 

Bilger) UG.) -74;, 79.145 

Emerson, R. W., quoted, 148 

Endymion, lunar form., 73 

Ephemeris, national, 82 

Equator, celestial, note 14, p. 32 

Equatorial mounting, 107, 109, 113 

Eratosthenes, lunar form., 77 

Eudoxus, lunar form., 74 

Eyepieces, 104; advantages of 
low powers, 109 


F 


Facule on Sun, 64 

Fecunditatis, Mare, lunar sea, 71 
Field-glasses, 3, 97, 99 

Finder, of telescope, 112 

Fiske, John, quoted, 114 
Flammarion, C., 145 

Flocculi, 67 


G 


Galaxy, 19 

Galilean glass, 98, 99 

Galileo (1564-1642), Ital. Astr., 70 
Geminids, meteors, 96 

Gill, Sir David, 16, 66 


147 





Great Bear, Ursa Major, 38, col. 1, 


134 
Greek alphabet, 33 
Grimaldi, lunar form., 71 


H 


Hale, G. E., quoted, Iv, 68 
Halley’s comet, 92, 94, 137 
Harvard Observatory, 10, 140, 144 
Harvard Photometry, 116, 140 
Hercules, lunar form., 74 
Herschel, Sir John, Eng. Astr. 
(1792-1871), 112 
Herschel, Sir Wm., Eng. 
(1738-1822), 126 
Herschel solar eyepiece, 64 
Holden, E. S., 68, 145 
Hour Circles, 106, 107, 117 


I 


Astr. 


Imbrium, Mare, lunar form., 71 
Iridum, Sinus, lunar form., 71 


J 


Jupiter, Table for finding, 88 
Jupiter, moons of, 89 


K 


Kapteyn, J. C., 66, 138 

Kempf, P., 66, 145 

Kepler, J. (1571-1630), 2 

Kepler, lunar form., 71 

Key-Maps for any hour, 30, 34, 35 
Klein’s Star Atlas, 145 


L 


Langrenus, lunar form., 71, 72 

Lenses in astr. eyepiece, 102 fol. 

Leonids, meteors, 96 

Lick Observatory, 33, IOI 

Light, velocity of, 9, 138 

Light-year, 9 

Lockyer, Sir Norman, 13, 14, 68, 
145 

Longfellow quoted, 129 

Lowell Observatory, 33, 87 


M 


Magnifying powers, 98, 104 
Magnitudes of stars, 10, 140 


148 


Mapping the sky, 4, 6 

Mars, Table for finding, 86, 87 

Mercury, 83, 85 

Meredith, George, quoted, 96 

Messer’s, J., Star Atlas, 145 

Messier, C. (1730-1817), French 
astronomer whose initial M with 
accompanying number (as M 31) 
is associated with the nebule 
and star clusters in his famous 
list, 126 

Meteors, 94 

Milky Way, 19 

Mira, 14 

Moon, the, 69 fol. 

Moons of Jupiter, 89; of Saturn, 91; 
of Mars, 86 

Moulton, F. R., 118, 123 

Mountains, lunar and terrestrial, 75 

Mount Wilson Observatory, 33 


N 


INebtlews S511 el5 at 7262 O,2 In esO, 
115 

Nectaris, Mare, lunar form., 71, 75 

Neptune, 9, 81, 82 

Newall, H. F., 145 

Newcomb, Simon (1835-1909), 

Amer, Astr., 105, 144 

Newton, Sir Isaac (1642-1727), 

English Astr., I 

Night-Charts for any hour, 34,35, 30 

Noble, W., quoted, 78 

North-star = Polaris, 22, 135 

Nubium, Mare, lunar form., 71 


O 


Objective =Object lens, 4, 98, 102 

Observation, practical hints for, 22, 
30, 110 

Observatory, The, 146 

Occultation of moon, 78 

Olcott,» Wien ra! 

Opera-glasses, 3, 97 

Orion nebula, 21, 130 

Orion’s apparent march, 25, 117 

Orionids, meteors, 96 


Pr 


Parallax of stars, 138 








£l Beginner’s StarzBook 


Peirce, lunar form., 72 

Perseids, meteors, 96 

Perseus, double cluster in, 4, 5, 131 

Petavius, lunar form., 72 

Photographs, astronomical, 33 

Photometry, Harvard revised, 116, 
140 

Photosphere of Sun, 64 

Picard, lunar form., 72 

Planets, 80; Tables for finding, 82 
fol. 

Planisphere, 146 

Plato, lunar form., 71, 7 

Pleiades, 17, 19, 134 

Pointers, 24 

Pole-star, Polaris, 22, 135 

Popular Astronomy, 146 

Posidonius, lunar form., 74, 75 

Position Angle, 116 

Potsdam Observatory, I0, 140 

Prism binocular, 3, 98, 99 

Procellarum, Mare, lunar form., 71 

Proclus, lunar form., 74, 75 

Proctor, R. Aly English Asim, 97, 
145 

Prominences, solar, 64, 68 

Proper motions of stars, 117, 138 

Ptolemy, lunar form., 76 

Puiseux, M. P., 66 


R 


Riccioli, G. B. 
135 
Rigel, 16, 130 


Right Ascension, note 14, p. 32 


(1598-1071)... 71, 


S 


Saturn, Table for finding, 90; rings 
of, 89, 91 

Schools, telescope in, Pref.; 108 

Schurig’s Atlas, 145 

Serenttatis, Mare, 71 

Serviss, Garrett P., 145 

Signs of Zodiac, footnote, p. 81 

Sirius, 9, 10, 121 

Smyth’s ‘Celestial Objects,” 145 

Spectroscope, 117, col. 2, 145 

Spica with Corvus, 26 

lars wCOLOLS 14) mos 
motions, 22 fol.; 


apparent 
proper motions 





and velocities, 138; variables, 13, 
142; double “stansyui2 weeulGe 
telescopic binaries, 12, 142; spec- 
troscopic binaries, 143; magni- 
tudes, 10, 138; distances, 9, 117, 
138 

Sun, the, 62 fol. 

Sun, motion in space, 66 

Sun-spots, 66, 67 


4 


Telescope, 3, I01, 102; eyepieces, 
104; mountings, 106 fol.; for 
schools, 108; practical notes for, 
30, IIO 

Tennyson quoted, 13, 17, 21, 22, 25, 
29 

Terminator, 71 

Theophilus, lunar form., 73, 74 

Todd, Prof. D., 91, 107, 145 

Tranquillitatis, Mare, lunar form., 
71, 74 

Tycho, lunar form., 71, 76, 77, 78 


18) 
Uranus, 81, 82, 126 
V 


Variable stars, see Stars 

Vega—Diagram, 28, 128 

Vendelinus, lunar form., 72 

Venus, Table for finding, 84 

Vogel, German Astr. (1841-1907), 
145 


W 


Webb, T. W., English Astr. Se 
1885), 78, 113, 145 


Ww 
Yerkes Observatory, 33, 101 
Young American Astr 
(1834-1908), 62, 68, 145 
Z 


Zodiac, Signs of, 80, 81 


“One might think the atmosphere was made transparent with this design, to give man, in the heavenly bodies, 


the perpetual presence of the sublime. 


Seen in the streets of cities how great they are! 


If the stars should appear 


one night in a thousand years, how would men believe and adore; and preserve for many generations the remem- 


brance of the city of God which had been shown. . 


We exaggerate the praises of local scenery. 


In every 


landscape the point of astonishment is the meeting of the sky and the earth, and that is seen from the first hillock 


as well as from the top of the Alleghanies. 


The stars at night stoop down over the brownest, homeliest common, 


with all the spiritual magnificence which they shed on the Campagna, or on the marble deserts of Egypt. ... He 
who knows the most, he who knows what sweets and virtues are in the ground, the waters, the planets, the 
heavens, and how to come at these enchantments, is the rich and royal man.’’—R. W. EMErson; Nature I; II. 


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